I'm ready to put a For Sale sign it in. Tail/stop fuse blows

[whitesswj]

I'm stumped...
One thing I love about my '68 is the fact that it's easy to work on - most of the time. But, MAN! If it's not one thing it's another.

I've lost my tail and stop lights. Keeps blowing the fuse on the tail light phase of it and I just thought to replace the fuse and see if stop lights work ok...

Any who, I pulled all 4 bulbs and replaced fuse to see if it would still blow and BLINK. Glowed and blowed!
So now I'm stumped. What else to look for?
I hate the electric part of anything. I have more luck with computers than I do old trucks.
Help a fella out..

[BadaSs_Cal]

When I got my truck the owner had the same problem... so in order to combat the problem he ran a wire from the brown wire (the power wire) all the way from the tailights to the engine bay and hooked it up to where the headlight/alternator junctions..( brilliant huh?) except that the maker lights turned to brake lights... anywho... long story short...

Check where you plug the bulbs in... if those little connections in there are touching... have fun replacing fuses..

Have you done any recent electrical work on it?

[Bulldog88]

Check the real small fuses that are located on the back of the truck by the taillight harness if those are blown the one on the fuse box will always blow also check for any striped wires touching metal
Posted via Mobile Device

[BadaSs_Cal]

I didnt have any fuses on my 69.. But I did end up fixing the PO hack job by making a new harness from scratch.. Small fuses you say? No wonder the lights are so bright..lol

[VA72C10]

I always start by checking the ground. Make sure the tail light buckets are tight to the bed.

[whitesswj]

Originally Posted by BadaSs_Cal

Have you done any recent electrical work on it?

yes and no.
I replaced the starter battery wire and didn't route it right and it created a dead short on the headers. I didn't realize that was happening and had the truck hooked up to another car for like 30 minutes two different times making very hot jumper cables and blowing a battery. So I had to very carefully replace the Hot wire one more time. But no, none major electrical.

[whitesswj]

Originally Posted by Bulldog88

Check the real small fuses that are located on the back of the truck by the taillight harness if those are blown the one on the fuse box will always blow also check for any striped wires touching metal
Posted via Mobile Device

.
Where are the small fuses at the back? Have a picture of them? This one is new to me.

Checked for the stripped wires and none found.
Thanks.

[whitesswj]

Originally Posted by VA72C10

I always start by checking the ground. Make sure the tail light buckets are tight to the bed.

Done

[dadsworktruck]

try unpluging the rear section light plug, if it don't blow a fuse at least you have narrowed your search for the shorted postive wire to ground, which if i was guessing (which we all are) i would say the bulb socket insulators are bad...but if fuse still blows, then go from rear plug up to fire wall plug check wire continuaty (sp)...

['70_402]

i know this might sound extreme, but i had similar problems, but more of them... and i just rewired the whole truck with a new painless kit... best thing i ever did...

[oldgold70c10]

Check the wire that runs under the driver's side door sill. It will be orange and white. It feeds the dome lamp and is on that same circuit. It is very vulnerable to damage.

[oldgold70c10]

And this will help too:
Color wiring diagram

[Sinister]

Originally Posted by Bulldog88

Check the real small fuses that are located on the back of the truck by the taillight harness if those are blown the one on the fuse box will always blow also check for any striped wires touching metal
Posted via Mobile Device

I've never heard of these either. Where are they located?

[whitesswj]

Originally Posted by oldgold70c10

Check the wire that runs under the driver's side door sill. It will be orange and white. It feeds the dome lamp and is on that same circuit. It is very vulnerable to damage.

Yes, I'll do that one.

[406 Q-ship]

You know it can be the turn signal switch too. The Brake lights run through the switch in the column. Does the fuse blow when it is put in the fuse block or does it wait till the brakes are applied?

[Clyde65]

Brake light switch?

[1970 Bowtie]

Originally Posted by clyde65

brake light switch?

x2

[67chevemall]

Originally Posted by dadsworktruck

try unpluging the rear section light plug, if it don't blow a fuse at least you have narrowed your search for the shorted postive wire to ground, which if i was guessing (which we all are) i would say the bulb socket insulators are bad...but if fuse still blows, then go from rear plug up to fire wall plug check wire continuaty (sp)...

x2

[VetteVet]

The orange wire from the fuse box feeds the dome and brake light switch. It also feeds the headlight switch to power the tail lights and parking lights. It's very easy to isolate which circuit has the problem. Leave every thing off, key and headlight switches, and step on the brakes. If the fuse blows then the short is in the brake light circuit or the dome light circuit. The sill plate short is very common and may be the cause for either the brake or tail light blowing the fuse.

Power for the turn signals comes from the purple wire from the fuse panel and goes up into the steering column. The turn signal wires and the brake light wires from the column are the same two wires, Green and Yellow and they run from the column connector to the firewall connector under the cab to the rear lights. If either of those two wires are shorted then turning on the turn signals would also blow the fuse. Normally the orange wire is not powering the turn signals but it runs through the TS switch and powers both the green and yellow wires that run to the rear of the truck for the brake lights, but not until the brake switch is activated. When either left or right turn is selected the orange wire for that side is disconnected and the purple wire from the flasher takes over. That's why the question by 406 Q ship is important. If the fuse blows immediately then the short is in the dome light circuit. If it doesn't blow until the brake switch is activated then it is in the turn signal switch or in the harness that runs to the rear of the truck for the brake/turn lights.

Now with every thing still off, turn on the tail lights and see if the fuse blows. If it didn't blow in the other trials but now it does then the short is in the brown wire circuit to the tail/parking lights.

Now you must be sure that you have the correct bulbs in their sockets and the correct fuse in the fuse holder because a fuse will blow if too much amperage is pushed through it as well as being shorted to a ground. I apologize for the long post and hope I haven't confused you.

[KEL]

Originally Posted by VetteVet

The orange wire from the fuse box feeds the dome and brake light switch. It also feeds the headlight switch to power the tail lights and parking lights. It's very easy to isolate which circuit has the problem. Leave every thing off, key and headlight switches, and step on the brakes. If the fuse blows then the short is in the brake light circuit or the dome light circuit. The sill plate short is very common and may be the cause for either the brake or tail light blowing the fuse.

Power for the turn signals comes from the purple wire from the fuse panel and goes up into the steering column. The turn signal wires and the brake light wires from the column are the same two wires, Green and Yellow and they run from the column connector to the firewall connector under the cab to the rear lights. If either of those two wires are shorted then turning on the turn signals would also blow the fuse. Normally the orange wire is not powering the turn signals but it runs through the TS switch and powers both the green and yellow wires that run to the rear of the truck for the brake lights, but not until the brake switch is activated. When either left or right turn is selected the orange wire for that side is disconnected and the purple wire from the flasher takes over. That's why the question by 406 Q ship is important. If the fuse blows immediately then the short is in the dome light circuit. If it doesn't blow until the brake switch is activated then it is in the turn signal switch or in the harness that runs to the rear of the truck for the brake/turn lights.

Now with every thing still off, turn on the tail lights and see if the fuse blows. If it didn't blow in the other trials but now it does then the short is in the brown wire circuit to the tail/parking lights.

Now you must be sure that you have the correct bulbs in their sockets and the correct fuse in the fuse holder because a fuse will blow if too much amperage is pushed through it as well as being shorted to a ground. I apologize for the long post and hope I haven't confused you.

Explainations like this sure do take the pain out of everything.

[Classic Heartbeat]

There isn't any fuses in the rear of the truck. If someone has fuses back there a PO installed them. Bad switches don't usualy cause fuses to blow, unless they have metal housings and are shorted inside. Then it wold blow the fuse wether or not the brakes were applied. Your switch seems to be working great as evidenced by only blowing the fuse when you apply the brakes. What you have is a short somewhere. Most likely in the rear section of the taillight harness. At least that is the section that most time gets hacked into for trailers. If not it would probably be in the intermediate harness. Both of these harness are exposed to the eliments and are brittle because of it. You can try to repair them, but that is usualy temporary at best. The best thing to do is to just replace them. This will eliminate any future problems. If you need a couple of new OE style harnesses we can supply you with them. WES

[cdowns]

also getting under the truck and checking the whole length of the wire harness that runs down the drivers side frame rail iis good to do especially where they are held in place by the clips on the frame// also look near the rear for butchered abandoned trailer light hookup attempts

[BadaSs_Cal]

Originally Posted by cdowns

also getting under the truck and checking the whole length of the wire harness that runs down the drivers side frame rail iis good to do especially where they are held in place by the clips on the frame// also look near the rear for butchered abandoned trailer light hookup attempts

Oh yes.. When I pulled my intermediate harness( wires that run from firewall to the rear crossmember and plug into the taillight harness, there was splices galore.... $7.99 at Pick N Pull... 5 minutes of work. These trucks are very simple for working on the light harnesses. I wouldnt waste the money on a painless kit unless the whole truck harness needs replacing.

[Classic Heartbeat]

I wouldn't waste my money on my painless harness. WES

[Mike J]

gotta have a short somewhere in that circuit- probably to ground...