Rewired 70 C10 heater and running lights on even if ign is not plugged in.

[C10Coloradoguy]

Thanks to all on this forum as I have gotten a lot out of it but am unfortunately still stumped because of my lack of knowledge/experience with auto wiring.

I have a 1970 C10 shortbed that I bought a brand new AAW harness for and have also upgraded the gauge kit (New Tach, Clock). I have installed it per instructions and all of the wires are marked making it fairly easy to tell what is what. On my first attempt to connect the battery, I burned out to wires on the printed circuit (alternator circuit, and "terminal next to battery" circuit. It was tedious but I was able to splice together the old board and the new board for a completed circuit that would fit around the tach. The issue was that the AAW diagram showed a pink IGN wire and a GROUND going to the BAT gauge but I now know that is not how these C10s are wired. Even though the circuit board fried, the heater, electric fan, and front and rear running lights were on in the key's OFF position.

Thanks to VetVette (who I hope doesn't chastise me too much for posting) and others on this forum, I was able to wire up the gauges correctly and the circuit board seems to be intact. However, the heater and running lights still come on after I hook up the battery (I unplugged the electric fan). After some reading I thought that one of the wires on the ignition was staying hot but I have them wired individually so I pulled them off one at a time and the heater and lights still stayed on. The dash lights (connected), the brake lights, and the reverse lights don't come on with their respective triggers though. Some notes below on the components:

Ignition switch and wiper switch = old
Headlight switch = new
Electric fan came with a relay mounted next to the battery that acts as a circuit breaker. Battery cable has extra wire to hook into relay.
Battery is hooked directly to starter with red harness feed and purple IGN wire
Power side of relay by the battery has been run to the BAT side of Battery gauge and spliced to number 12 wire on dash cluster plug
A/C Heater lamp did not have a specific wire so left out. Still not sure if that little lamp completes a circuit or not, would need to splice if so.
The voltage regulator has been deleted from the harness
Haven't connected courtesy ground wire (currently capped) to anything yet as I need to wire dome switches


Thanks in advance for any information.
I appreciate any help that this forum can provide. Thanks!

[C10Coloradoguy]

That is a lot of crap to read. Here is the short version: What would cause the running lights and heater to come on with the key in the OFF position?

[C10Coloradoguy]

OK, so here is what I did: Either because I had it bookmarked or it automatically popped up when I popped in (kudos to the programmer if this is the case!) so I printed a few pages out and took them to the cab and hooked up the dome light. Lo and behold that worked, for the dome light. Same thing with the running lights on at all times.

After studying the diagrams and back tracking a couple of connections, I kept coming back to the brake switch (orange and white wires). Just to try everything, I switched the leads on the switch itself and put the negative lead back on. Something different! The hazards came on. Reached in and turned them off (which worked!). No running lights but the headlights still worked. Reached in and pushed the brake and sure enough, they worked. Left right turn signal do not work though (didn't before either).

So my assumption is that the brake switch is correctly wired now. Going to figure out the rest of the puzzle tomorrow. Input is welcome but I will post results tomorrow regardless.

[C10Coloradoguy]

Thanks to all of the contributors on this forum for their documentation and knowledge on this forum. Still getting stumped by this one and here is where I am at with it:

I came down to blowing out the 10 Amp BRK/CTSY fuse every time I pull the switch to turn on the dash lights. So, like anyone would, I searched for this problem and it brought me to this forum on this particular thread:

http://67-72chevytrucks.com/vboard/s...d.php?t=596221

This is an AAW harness similar to mine but not quite the same. However, he seems to be describing the same issue and unfortunately the thread was never solved. Here is a diagram of my fuse box. I've tried to make it abundantly clear which fuse is popping.




Notes: This AAW harness came with 2 orange wires marked "12v fused" but on the diagram it has an orange wire for "courtesy dome feed" but no wire in the bundle is marked as such. Just a 2nd 12 fused. The dome light does work when hooked up to a 12v fused wire but if it shares power with the brake switch or the light switch, it pops the fuse shown above above when pulling the light switch to the dash/running lamp position. My harness comes with two separate wires for both sides of the brake switch. The brakes work fine when wired this way but adding the courtesy dome (which by the way is how all the diagrams I have seen says to wire it) pops the fuse marked BRK/CTSY and the dash lights don't work. I need to take a break on this as it is driving me mad.

[C10Coloradoguy]

Orange light switch wire (marked 12V fused) wired directly back to panel (per AAW and full C10 color diagram). Brake Switch wire (in AAW harness but not in C10 diagram) wired directly back to panel as originally done. Courtesy lamp removed completely as it does not appear to be part of the puzzle. Double checked grounds and checked to see if any wires were open. Nope. Same fuse is popping.

[VetteVet]

Well this is a new first A selfie thread.


I wouldn't ever chastise anyone for posting, but I must say that your bold font is a little hard on the eyes. I see that you discard that so thanks for that.


Now I also see by your attachments that you are using the AAW fuse panel which is different than the good ole GM version. This makes for the possibility that you have mis-wired the panel. I have not had experience with this panel but I assume the harness that AAW makes is very similar to the OEM version.

If that's the case then you will have a large red feed wire from the main junction into the cab which feeds the panel, the horn relay, the ignition switch, and the headlight switch. These are the feeds for all the key off functions of the truck.
Horn, Brakes, Hazards, cigarette lighter, and headlights including dash and tail lights.

The fuse panel feed is expanded by an orange wire which feeds the headlight switch for the Tail lights and the dash lights and it feeds the stoplight switch and the dome light fuse.

I've posted it before but here it is for those who may have missed it.



As you can see the red wires come into the cab and form a junction then each wire goes to the location I described. The key switch and the headlight switch are not shown in this diagram. I'll put it below.

The orange wire is shown at the fuse panel in the lower right corner with the dome light connector. Notice the connector also has a white(shown as black) wire which is the ground side of the dome light and it is the side of the circuit that is switched by the door switches and the headlight switch knob when rotated. Is it possible that you have connected the white wire with the orange wire which goes to the headlight switch?


Just for information this diagram shows two other sets of wires that provide power to the fuse panel for "key on" functions.



The pink wire from the key switch which feed the ignition coil and the fuse panel for the cluster feed fuse.

Then we have the 12 gauge brown wire from the key switch accessory terminal (shown by the arrows) which feeds the wiper fuse, the heater/AC fuse, and the turn signal flasher.

Here is the other diagram showing the Key and headlight switches

[C10Coloradoguy]

Oh man, I've just skimmed through the post because I'm too excited! Thank you VetVette! I am going to print your reply and jump back in. Getting a response directly from you gives me the confidence to solve this. I'll report back soon.

[C10Coloradoguy]

Selfie thread helps me think. Many a time I have started typing and then in the middle of it, jumped up and headed back to the garage.

In answer to your question, no, the courtesy dome is wired correctly (or left out as it is now). The difference appears to be that AAW included the white wire marked "ctsy ground" specifically (just as the brake switch wires above have their own wires).

You mention the orange feed wire from the panel. I've included a shot of the AAW harness below:

http://imgur.com/a/2wMTu

The harness does not have a wire marked "ctsy dome feed" (wouldn't you want an item like this to match exactly with the chart?) but has an orange wire marked "12V Battery Fused". My guess is this is what is supposed to feed the Ctsy Dome. However, this truck has been pieced together with a Muncie 4 speed and the reverse switch is mounted on the tranny underneath the bell housing at the base of the shifter. The 12V Battery Fused wire is currently feeding the backup lamp switch which I haven't found on any of the charts, but it works with 12V fused power.

Now, in order to incorporate the dome since I have it, I have spliced it to 3 different 12V fused wires. Here were the results:

Spliced to 12V fused feed going to backup lamp switch. This allowed the dome to work until I pulled the light switch (1st position) which shorted the fuse and thus the reverse lights.

Spliced into orange "brake switch" wire (as is shown on the OEM chart). Figured this would be my best option as it was closest to the original but had the same result.

Spliced to the orange 12V fused wire that comes directly from the switch and goes back to the panel. (Looking back I wish I hadn't done this but I will try anything) and got the same result.

Currently: All 12V fused functions have their own source directly from the panel but the courtesy dome is not connected.

If you look at the AAW chart, Circuit Branch 5 is for accessories and port 102 is another 12V fused feed. This is either for the lighter or spare 12V fused power. I currently have the lighter hooked up through this connection and on the advice of a friend I have double checked and there is not a penny at the bottom. I have seen evidence of accessory and light sockets causing issues but don't know for sure if that may be the case here.

The other difference is that on the OEM chart you have the gray wire (Cluster LP.) feeding to the cluster plug and then out to the A/C heater lamp. Currently I don't have an A/C heater lamp so the gray wire on the AAW harness (branch 7 marked "dash lights" because this is the ONLY gray wire on the harness) is connected to the the cluster plug but the gray wire going out to what should be the A/C heater lamp is capped.

This is a lot of information but hopefully someone with superior knowledge can decipher this.

[VetteVet]

All your experiments have one thing in common. No matter which power source you use for the orange wire to feed the dome light, It gets shorted to ground through the headlight switch.

The white wire is the ground for the dome light circuit even as stated by the AAW instructions.

It appears to me that the white wire is grounding the orange wire when you pull the HL switch knob out.

With the truck battery disconnected and not power on the electrical system, check for continuity between the white and orange wires when you pull out the knob. This is without the dome light bulb inserted. The orange wire should only have continuity to the white wire when it has the dome bulb inserted. Also the white wire is only grounded when either door switch is closed or the headlight switch is rotated all the way C/W.

The battery power fuse for the orange wire is the same as the red wire in the OEM fuse panel and should not affect anything, which it isn't if the brakes are working and the brake lights fuse is not blowing. The fuse panel from AAW is just expanding the number of circuits that are fused more so than the OEM panel.

The reverse lights circuit is one of the simplest in the whole truck. You have power to the reverse lights fuse and one wire from there to the reverse light switch and the same wire goes from there to the rear end where it splits and goes to each light. When you put the transmission in reverse, it closes the switch and power goes through the wire to the reverse lights.The manual transmission uses a switch on the transmission or the gear shifter and the automatic uses the neutral start switch on the steering column. Most of the GM vehicles use a dark green wire and a light green wire for this circuit.

I hope this helps you find the short. VV

[C10Coloradoguy]

Ok, "A result". Hasn't quite answered my question but we are much closer to finding the cause.

So, I took the board off the firewall and checked the back of all the lines. No burns. But it allowed me to verify where each wire should be wired to. So, after some minor rewiring, here is where we are:

Orange 12V fused wire on the headlight switch is wired directly to the block. This is at the back of the PARK LT 10 amp fuse (red) on the block. I verified this on page 3 of the AAW instructions where this wire on the switch plug is clearly marked "Fused Battery Feed (for parking lamps) from dash harness (ORANGE)". The orange "brake switch" wire is wired independently to the brake switch as originally intended by the AAW harness. The mystery 12V fused orange wire is now wired directly to the orange side of the dome light and the white ctsy ground wire is wired directly to the white wire on the dome light and the light is in the "clip".

Incidentally, I did take VV's advice and checked for continuity between the orange and white wires directly from the headlight switch since I had access to both of the bare wires. I was really really hoping it would show 0.00 ohms when I pulled the switch but no, no such luck.

So, after hooking the battery back up, I reached in and twisted the headlight knob to the left. No dome light. I would come to realize that I hadn't put the BRK/CTSY fuse back in (I only have 2 left) but that was before "the result". The dome light wasn't working because there was no fuse in place to allow it to but when I pulled the headlight switch to first position: POP A nice clear short on the fuse block popping the PARK LT 10 amp fuse.

So we are back to the orange wire coming directly from the headlight switch giving us a result. Why though is it popping fuses? And would it had made a difference if I had the BRK/CTYS 10 amp fuse in place?

[C10Coloradoguy]

Just a note: I realize that the issue may actually be the headlight switch even though it is new and came with the AAW harness. I suppose I can open it up and take a look but I'd hate to break the damn thing even if it doesn't work right.

[C10Coloradoguy]

Ok, forgive me if this is just review of the above but I'm not a professional and this is my first auto wiring job. I've done residential and know how to check for volts and continuity with a multi-meter but that's about it. Just very very persistent.

I am pretty convinced I have it wired correctly. I redid the ground on the front end so that there is no doubt the grounding is good. Pulled the switch and the PARK LT fuse popped (as expected) so we can pretty much verify the orange wire, or something it is connected to is causing the issue.

Since I had the block off of the firewall, I decided to do a continuity test on the back of the block with the orange wire socket and all of the wires from the block leading out. This probably doesn't surprise an expert but there was some resistance on all wires except for the two gray wires coming out of the bottom of the block which are for the dash lights.

One wire goes out to the cluster plug and one runs directly back to the headlight switch. The cluster plug is the old plug that I spliced into the harness and the dash is where I have the questionable circuit board. Bottom line is tomorrow I will be taking the dash off (again) and checking for shorts back there. At least I have a direction.

[VetteVet]

Well if you have a short to ground in the circuit board you would certainly pop the PNL LTS fuse when you turned on the headlights. The pnl lts fuse for the dash lights gets its power from the orange wire on the headlight switch after it goes through the rheostat (dimmer) in the switch, via a green wire back to the fuse panel.

When a harness comes with a new fuse panel where different fuses may split circuits, it becomes harder to isolate exactly which fuses are fusing which circuits. it makes it much harder for anyone (me) without hands on, to isolate the short. I guess what I'm saying is that your courtesy dome fuse must be fusing the dash lights, from your details, and I don't remember reading about a problem in the circuit board. That would have been a big clue but it still wouldn't explain why the Pnl Lts fuse wasn't blowing first, unless like I said, maybe they don't use it and are using the Courtesy lights fuse.

[C10Coloradoguy]

Thanks VV. I really appreciate your comments and thoughts and understand that doing a "hands off" diagnosis is less than desirable.

Quote from first full paragraph on first post: "On my first attempt to connect the battery, I burned out to (TWO, oops) wires on the printed circuit (alternator circuit, and "terminal next to battery" circuit. It was tedious but I was able to splice together the old board and the new board for a completed circuit that would fit around the tach. "

So in essence I have stitched together the circuit board and it maybe worth mentioning that I have LED lights in the dash instead of the standard bulbs it originally came with.

At one point in the thread it seemed to be the BRK/CTSY fuse causing the issue. Also at one point when I had it wired incorrectly (don't remember the exact configuration) It did blow both the PARK LT and the BRK/CTSY fuse but now that I am certain the wires are running to the correct places, it is definitely the PARK LT fuse that is consistently blowing.

Even with my inexperience this seems to be leading back to the dash and since VV seems to concur, that's where I will be searching today. I'll let you know what I find.

[C10Coloradoguy]

My "try it" method:





The blue board is the original board I bought with the truck. The bottom two tabs on the original circuit (2nd picture) were missing so I can't even verify it worked in the first place.

This would be an obvious place for it to be grounding so I'll have to remove the dash...again. Hopefully 3rd time is the charm.

[C10Coloradoguy]

Finally got behind the dash. Found two things. An open ground wire which could have been affecting all of the dash wiring, or the more likely culprit of my patchwork circuit board which I have tested and have not been able to get to work properly no matter how much surgery I perform. I'm ordering a new circuit board and will post results.

[Yotapane]

Originally Posted by C10Coloradoguy

Finally got behind the dash. Found two things. An open ground wire which could have been affecting all of the dash wiring, or the more likely culprit of my patchwork circuit board which I have tested and have not been able to get to work properly no matter how much surgery I perform. I'm ordering a new circuit board and will post results.

I had a similar issue and found the harness to the turn signal switch rubbing against the steering column...

[C10Coloradoguy]

Thanks Yotapane. I will look there too. Those wires that run up the steering column are original and although I've looked them over once or twice, I will go over them very very carefully one more time.

[C10Coloradoguy]

I got a new job so have been away. Some things have changed but the results are the same: The PARK LT fuse blows every time I pull the light switch to first position.

I have gone through the switch and as far as I can tell it is functioning properly. The orange Fused Battery Feed wire is on the circuit that keeps blowing. On the other side of the fuse is a red jumper wire that jumps down to one side of the LIGHTER fuse and the other side of that fuse runs out to the Accessory Feed Wires connector that control various accessories (pwr windows, locks, etc.) I found that I had the lighter incorrectly connected to what was supposed to power the pwr windows. I hoped beyond hope that this was the problem, but no.

I received a new circuit board, verified all connections, looked over all wires and checked all connections front and back. I don't know wtf to do now.

[C10Coloradoguy]

Retraced wires for the back end of the vehicle and verified some connections on the front. Unable to find any short/damage/exposed wires. Still popping the same fuse but I have a question: On each side of the front end of the truck, under each wheel well is some type of electrical junction. They both have a single wire coming out of them and I am assuming these are the fusible links to hook up the Battery/Voltage gauge. Is this correct or do they need to be wired in a particular way in order for everything to work correctly?

[C10Coloradoguy]

Well, some success. After pouring over schematics and different connectors, I found that I had the Park Lights wire connected to the turn signal side of the front marker/turn lights and this was grounding the wire out at the light(s). I reversed this and rewired so the side marker lights are on the brown Park Lights wire as they were wired to turn signal connections. I have read that I could throw a wire from the signal side of the front marker/turn to the side park lights and then they would be both "on" and signal. Although this is what I want, I am concerned it would just ground the Park Lights wire again. For now, I have wired the side markers to the brown wire so that they are Park Lights only, and reversed the wiring on the front marker/turn, then hooked the battery back up.

Tested the dome light which worked as expected. Pulled the switch to first position and the fuse held!!! The side markers came on and the headlights worked (they always have though). But my dash lights don't seem to want to light. Now, in testing other circuits, I turned the key to first position and tried the left turn signal. Nothing. Then I tried the right signal. Nothing...POP! Turn signal fuse blows. I have been through the switch and I believe it might actually be the original switch that was installed on the truck. It's kind of gummy on the inside and the straight springs like to pop out. I'm going to find a new turn signal switch and move forward and also research why my dash lights don't want to light.

[C10Coloradoguy]

Gee C10CG, I sure would like to see those dash lights light up. Maybe because they're LED and should give a cool glow to the dash. Did you hook up the dash lights after you took them off the circuit?

So guess what? I have dash lights. A couple or a few don't seem to be working but that is most likely from improper wiring and not running through the circuit board correctly. Fortunately I haven't fried any more boards.

I would love some direction or confirmation on how the "Battery" or voltage gauge should be wired as I believe this is one of the dash lights that is not working. I have one side wired to the alternator and one side to 12V power but they are not run through the junction boxes under the wheel wells. Are these necessary for resistance or something similar?

Thanks.

[C10Coloradoguy]

OK, dash lights and park lights appear to be working. I ordered a new turn signal switch and installed it. Also, I added the little light for the heater control. I hooked up the battery and once the ground cable hit the terminal: zzzz-pop....pop. OK, more fuses blown.
So now when hooking up the battery the HAZARD (15a) and the P WINDOWS (30a) fuse are blowing immediately. They are on the same circuit so it makes sense but what would cause these wires to draw too much current?

[C10Coloradoguy]

Ok, so after double checking the circuit, I found I did not have the clock wired. I wired this up and it appears to work but when the battery is grounded, the HZRD fuse blows right away. PWDOWS seems to be holding for now.

[C10Coloradoguy]

So the hazard fuse was blowing because I had the knob pushed in so the hazards were "on". I pulled out the knob to turn the hazards "off", reconnected the battery and the hazard fuse held. I turned the key to the first position to test the turn signal and when I pushed up on the lever for a right turn signal, the Turn Signal fuse popped. I checked both flashers and I think they're ok but I'm not sure. Going to start tracing wires again.