New headlights installed -with pics

[boxrodz]

Originally Posted by Zoomad75

I used heavy gauge wiring for the power side of the relays. At least 14, might have been 12 but I'd have to go open the hood again and look. As for the actual current draw, I have not put an ammeter on it. I based mine on a 30 amp load on some research I did on the net as well as the original setup. I knew since I was going to have an increase in voltage to the lights, I had better make sure the rest of the system was capable of the job. The relays I used were rated for 30 amps as they were the replacement relays available for the aftermarket foglight kits at most chain parts stores. The same relay was used for 50-60 watt fogs to the 100 watt off road lights. 30 amps might be a little overkill but I figured anything less would have me replacing the fuses when ever I switched the lights on. As far as protection goes, 30 amp fuese snap just as quick with a dead short. More like *POP*...

I havent noticed a larger draw on the system with the H4's over the halogens though. I don't see any dip on my voltmeter when I switch the lights on. Even when I hit the 100w fogs.

I could look at mine tonight and try to take a current measurement, but I can't remember what the limit is on my DVOM for ammeter. I think it might have a 10 amp limit, but I'll look. I could use a nice Fluke meter with the inductive ammeter pickup though for xmas!!!

Thanks for info, Zoomad75.

I'm running quads, so I'm considering a DPST Bosch relay and 12 AWG wiring to reduce the resistive voltage loss (drop) and improve the light output. Depending upon whether I change the conversion configuration, I may have to step up to a 30 amp fuse. I'm currently running Silverstars.

I'm not sure of the voltage at the headlight connectors. With the stock configuration, it's probably not what it could be. And, I hesitate to measure the current. My DVOM is only rated up to 10 amps. My analog VOM is probably much less. At this magnitude. I've blown meters trying to measure current. An expensive mistake back in the day.

Flukes instruments are nice...

[79BIG10]

Zoomad- Can you post a supply list and how you did it on the wire harness setup? I think I have an idea on most of it but want to make sure to get it all right the first time. I've wired in my electric fans with relays but not sure how to do it with the lights being bright and driving lights.

[wessscott]

I just got the LMC harness in and the chinese is excellent. Unfortunately I cant read chinese. From the way the diagram shows the two red wires that should be fused go to the battery. What do I hook to make the lights work off the headlight switch? The way I see it the lights are hooked to the battery then to the relay which should always keep them on. Any help is appreciated if you havr done the LMC hookup.

[C&C Chevy]

Originally Posted by 79BIG10

Zoomad- Can you post a supply list and how you did it on the wire harness setup? I think I have an idea on most of it but want to make sure to get it all right the first time. I've wired in my electric fans with relays but not sure how to do it with the lights being bright and driving lights.

Zoomad, we need cheapy diagrams!!!

[75silverstep]

Originally Posted by wessscott

I just got the LMC harness in and the chinese is excellent. Unfortunately I cant read chinese. From the way the diagram shows the two red wires that should be fused go to the battery. What do I hook to make the lights work off the headlight switch? The way I see it the lights are hooked to the battery then to the relay which should always keep them on. Any help is appreciated if you havr done the LMC hookup.

I PLUGGED MINE INTO THE OLD LEFTHAND HEADLIGHT PLUG ...WORKED FOR ME .NOT SURE IF THATS CORRECT BUT QUICK FIX TILL I FIND OUT OTHERWISE..

[Zoomad75]

Originally Posted by 79BIG10

Zoomad- Can you post a supply list and how you did it on the wire harness setup? I think I have an idea on most of it but want to make sure to get it all right the first time. I've wired in my electric fans with relays but not sure how to do it with the lights being bright and driving lights.

Here's how I did it. After figuring out the wire colors for what went where to the lights, I drew up my own diagram. Here it is: (Mine is a 75 remember, but should work up to at least 80, or later single headlight trucks)



If you are working on a later truck, verify your own wiring first and then use my schematic as a starting point. dual lamp trucks (4 total) works similar except for the fact that the high and low beam circuits go to separate bulbs. (don't forget another relay so you can kick your low's on when the high beams are selected)

Back to what I did on mine.....Here's your shopping list:

2 30 amp relays
2 30 amp inline fuse assemblies
2 rolls of 14 gauge wire (2 different colors)
1 package of shrink tubing
1 package of female spade connectors (I got the weather proof kind with heat shrinkable ends) get at least enough for 4 connections at each relay!
1 package of ground eyelets

Tools needed:
Wire cutters/strippers
Soldering iron and solder
Lighter for shrink tubing/spade connectors

Here's what I did. I planned on putting the relays directly above and behind the d/s headlamp on the backside of the radiator support. I did this for two reasons, ease of access (not hidden by the battery) and its close to where the headlight wiring comes from the fender/cab. Knowing where I wanted to put the relays, I could set the length of wire I needed to power up each relay as well as the ground wires for the relays. I decided to pull the power from the junction block on the firewall (just above and to the left of the brake booster) as I hate having a billion wires tapped off of the battery. I routed the wires in the same split loom that the stock headlight wiring ran in on the inside of the d/s fender. This way it's all hidden except where I put the inline fuses nearest the junction block. I could then hook up the power wires to the 30 terminal on the relays (keep the fuses out so you don't have a hot circuit to play with). I then hooked up the ground wires I made up with the female spade on one end and the ring terminal on the other to the relays and ground on the radiator support.

Now we need to get the switched on signal to the relays and output to the lights. This is where I was different than the LMC kit. I cut the brown and green wires that led to the d/s headlamp (don't make the cut in the wires to the p/s bulb, see the imortant note below). Each wire is still used, just the relays will be inbetween the where the circuit was cut.

****VERY IMPORTANT: the stock headlight wiring is set up in a parallel circuit. If you notice at the d/s headlamp the lamp connector will have two of each wire (brown and green) going to it. If you peel back the conduit you will see that one set of the brown and green wires actually goes to the p/s headlamp. This is a clever little wiring trick the GM engineers did to eliminate having 4 wires from the dimmer switch to the lights. Still before and after this mod, if the d/s headlamp bulb fails the p/s light will stay lit. (not like a cheap set of xmas tree lights!) ****

Anyway, with the brown and green wire cut, add the female spade connecters on both sides of the cut. Meaning on the switch side and the side going to the d/s light. Depending on where you made the cut, you might have to add a few inches to each side of the brown and green wires to allow enough slack in the wires for easy connection to the relays(try and use the same colors if you can to limit confusion later!). Following the schematic, you then hook up the brown wire from the switch side to terminal 86 on one relay and then the other brown wire to 87 terminal of the same relay. Do the same for the green wires to the same terminals on the other relay and you are done with the wiring. secure the relays to the radiator support, make sure you got all connections tight and recheck your connections to the relays. You should have both brown wires to one and green to the other. If you have a brown and a green wire to each relay, your dimmer will work backwards. Don't do that! Stuff the wires back into conduit/split loom, put the fuses back in the inline holders and hit the switch. LET THERE BE LIGHT!

One thing I would like to change on mine after seeing the LMC harness is the connections to the relays. Having 1 connector with 4 terminals to the relay would look a lot cleaner than 4 individual spade terminals. Plus you would be less likely to reconnect it wrong if you ever had to replace a burnt out relay.

You can see the one major difference in my setup to the LMC kit is that you cut the wires to the d/s headlamp and use the existing headlamp wiring/sockets whereas the LMC kit does not have any cutting and supplies new wiring/sockets for the headlamps. This is your call if you want to cut your stock harness. The LMC kit is Completely and quickly reversible, take the stock headlamp socket from the LMC kit and plug it back to your headlamp to go back to stock. This is a bonus if you are out in the boonies and a relay quits. My setup can be changed back to stock, but you got to splice the two wires back together. I'll carry an extra relay with me if one was to fail.

One other thing, since my setup uses the stock wiring at the bulbs, you might be inclined to ask why with the smaller stock wiring? I used mine, because the stock wiring was free of any corrosion (benfits of colorado not using salt in the winter) and the resistance was just as low as the same length of 14 gauge wires. That and the fact that the wiring for the p/s lamp was tucked well under the top of the radiator support and I was too lazy to fish it out. Basically, that is going to be a judgement call for you to make. If your stock wiring is thrashed and corroded, rewire the lights with fresh wire and new connectors. rewire it just like it was factory so you don't have two wires crammed into one terminal at the relay.

One last disclaimer, USE THIS AS A GUIDE. Your wiring colors may vary by year of truck. Use the GM service manuals for the stock schematics on the later trucks (chiltons or haynes are not perfect in this area). If you don't have access to a Gm manual, break out the test light and verify the color/purpose of each wire your self.

Hope this helps! NOW:

[Zoomad75]

Originally Posted by 75silverstep

I PLUGGED MINE INTO THE OLD LEFTHAND HEADLIGHT PLUG ...WORKED FOR ME .NOT SURE IF THATS CORRECT BUT QUICK FIX TILL I FIND OUT OTHERWISE..

Based on how the wiring is set up on a stock truck, plugging in the LMC kit at either headlamp socket will work. They just use it for the *ON* signal from the headlamp/dimmer switch. Dirty Larry hooked his up the the p/s (right) light, but he also put the relays over there by the battery too. Kept it hidden between the battery and the radiator support for a stealthy install. Larry's a bit more of a clean freak under the hood of his than I am even though it's pretty hard to see that area when the truck is lifted 4" on 35" tires..... I'd suggest that location too for a clean install, even more so for you 2wd low rollers.

[79BIG10]

Thanks Zoomad75. That looks great. I'll be working on the upgrade now thanks to your pic and write up. Maybe Jeff can post this on 73-87.com for others to look at.

[boxrodz]

Originally Posted by wessscott

I just got the LMC harness in and the chinese is excellent. Unfortunately I cant read chinese.

Originally Posted by wessscott

From the way the diagram shows the two red wires that should be fused go to the battery. What do I hook to make the lights work off the headlight switch? The way I see it the lights are hooked to the battery then to the relay which should always keep them on. Any help is appreciated if you havr done the LMC hookup.

Like Silverstep75 and Zoomad75 eluded to, you should be able to control (switch on/off) the battery power coming thru the relay into the headlamps by connecting the LMC harness to the stock headlight connector. Power is relayed to the headlamps thru the relay only when voltage is applied to the control pin of the relay. When no voltage is applied to the relay's control pin (headlight switch off), the headlamps will be off even though the battery is connected the relay (input pin) and the relay (output pin) is connected to the headlamps.

[boxrodz]

Great write-up, Zoomad75.
You pretty much got everything covered... other than the instructions in a 'different' language.

I put a schematic together for the quad 81-87 configuration, although it hasn't been verified. The mods are highlighted in blue. It's very similar to the diagram that you posted. In fact, the hi-beam headlamps can be omitted from the diagram which then can be referenced for 73-87 dual headlamp setups. The stock quad setups have hi beams and hi/lo beams headlamps. So, under the stock configurations, all four headlamps are on when the hi beams are switched. I believe stock setups use 18 AWG for the lo-beams and 16 AWG for the hi-beams. For the mod, I prefer 12 AWG if higher wattage headlamps are used. It's recommended to place the in-line fuses as close as possible to the power source (i.e. near the junction block). However, for a cleaner look, a single larger gauged stranded wire is pictured between the junction block and location of the inline fuses/relays. Also, the pinouts for the popular Bosch relays are shown.

BTW, my guess is by reducing the voltage loss at the headlamps should also slightly decrease the current draw from the headlamps.

[C&C Chevy]

Great work guys! Jeff should definitely put both of these on 73-87.com!

[Zoomad75]

Originally Posted by boxrodz

Great write-up, Zoomad75.
You pretty much got everything covered... other than the instructions in a 'different' language.

Different is how I do things. Actually, I just scribbled the schematic in MS paint so I could visualize the wiring to the relays. (I have a short attention span) It is overly simplified, but I think it still gets the point across.

Glad to help.

[boxrodz]

Originally Posted by boxrodz

Great write-up, Zoomad75.
You pretty much got everything covered... other than the instructions in a 'different' language.

Originally Posted by Zoomad75

Different is how I do things. Actually, I just scribbled the schematic in MS paint so I could visualize the wiring to the relays. (I have a short attention span) It is overly simplified, but I think it still gets the point across.

Glad to help.

Actually, it should of read something like 'You spare us from having to translate your write-up from some 'foreign' language (like the xū zhī that's in those wài xiàng xíng kits).

Thanks again.

[Zoomad75]

Originally Posted by boxrodz

Actually, it should of read something like 'You spare us from having to translate your write-up from some 'foreign' language (like the xū zhī that's in those wài xiàng xíng kits).

Thanks again.

Thats cool. I do have to admit when I saw the instructions from Dirty Larry's kit I had to laugh. LMC could not hide the outsourcing on that one could they! Hopefully we won't find out later that the harness' were assembled by some greasy back room sweatshop with 10 yr old child labor.

[Jim85IROC]

that harness looks exactly like the APC harness right down to the lame yellow tubing that's over the wires. I doubt LMC had anything to do with the design or production of the kit. All they're doing is buying it to offer with the headlights.

[bigblock73]

If anyone wants to take the time to summarize all of the above mentioned info (and VERY good info I must add) into one article, I would be glad to make it an article on the garage section on 73-87.com for everyone to see/use.

I personally could take the time to try and combine all of this, but it would be better if those of you who have performed this would do it...for accuracy and completeness.

[Zoomad75]

I've got some time off this week...I can see what I can put together. I've got some pics of the process, but can take more if need be from what is on my truck. Let me know what kind of format you would need it in.PM me here with any details.

[Russell]

I've got an article that I wrote about this, I just need to collect a few pics, and it'll be done.

You can do some proof reading, and see if I forgot anything. Lemme know how you format your html on your site, and I'll re-send it to you in an htm document with all the pics etc imbedded so all you gotta do is toss it onto your server, and add a link

[bigblock73]

Hey guys, I use Frontpage...so simply put it in a Word doc, supply the pics, and I can/will do the rest.

Since there is more than one of you who have done this, we can merge all the info together and have multiple authors if that is cool with everyone? This way, we know all the bases are covered.

[Russell]

not a problem at all I sent a rough draft of the word document to your email, once my camera finishes charging, I'll get the pics done

[C&C Chevy]

Great job guys. This is something that would benefit alot of us. The headlights on these trucks weren't exactly high performance.

[DirtyLarry]

I’ll snap some pictures tonight of the 30 Amp mini fuses that Zoomad suggested I install.

[DirtyLarry]

Here are the two 30 Amp mini fuses that were placed in the power leads to the relays. My battery has top and side posts so I used the top post to power the relays. Picture isn’t that great so if it helps great if not no biggie.

[Zoomad75]

Originally Posted by bigblock73

Hey guys, I use Frontpage...so simply put it in a Word doc, supply the pics, and I can/will do the rest.

Since there is more than one of you who have done this, we can merge all the info together and have multiple authors if that is cool with everyone? This way, we know all the bases are covered.

Email sent with my write up. I included Boxrodz schematic in addtion to my own. I don't have Boxrodz name to give credit where it's due so if he could chime in to get recognized for his drawing...

[Russell]

Here is a quick picture of my headlight relays, and distribution block.

The distribution block will be fed by a 30 amp fusible link, since my electric fans will draw up to 90 amps on startup, and I'd be constantly burning out fuses.

I have been able to have my high beams, and low beams on, then start both fans at once, and not burn up the fusible link, but shorting another spare one I had to ground burnt it almost immediately, so I should be good to go.

And yes, I will be getting another wire loom "T" connector so I can hide that open spot, and yeah, I haven't gotten my ground wires hooked up, nor my permanment power feed for the distro block.