NEW GUY

[73SWBBB]

Hey all, I've finally decided to get another truck and one I think i'll be pretty passionate about this time around. Its been hacked up a little before me but it is otherwise a complete truck and something I'm going to daily drive for a while. I'll have to get some pictures up of it some other time but Im sure it will be soon. I did a google search but decided it would benefit me most by joining this forum and finding some answers to my first issue with the truck. All lights work, except my tail running lights. Any ideas? Any help would be appreciated. Thanks guys.

[beastie_3]

something is disconnected, grounds arent good, bulbs are out.

[73SWBBB]

Something is disconnected? Bulbs out? Grounds? Really? Everything works except the running lights. So its pretty clear the bulbs are in and all switches are connected as well as having proper grounds. Otherwise nothing would work. I was hoping someone might have had the same issue and was able to troubleshoot it down to something a little more specific. The system seems extremely simple. The only component that might cause some weird stuff like this seems to be the switch. The bulbs are double filament so just one of the filaments in both bulbs isn't getting its ground or power. Whether its a voltage, ground or a current issue I haven't been able to figure out yet but plan to get the meter out this weekend so I can drive it comfortably at night. Any other useful insight would be greatly appreciated.

[beastie_3]

ya really. search the forum. there is a wiring diagram in the tech section. trace all your wires since its hacked up

[bake74]

     There is a connector in the back and at the firewall, the running lights work off a separate wire from the brake lights.  Start in back or up front to trace that wire/circuit to find out where you are loosing power, all the way back to the switch.
     This did happen to me on my 74 and it was the ground strap from frame to bed.  On mine the brake lights, reverse, and blinkers worked eratically, but no running lights.  So yes it could be a ground, the brake/running light is a combo light which needs grounds for both sides. For some reason it seems the running lights are more finicky.
     Welcome to the site also.

[73SWBBB]

Alright, so after digging through this truck Ive found that someone has gone through and done a swell job of wiring it up. There is a painless harness or at least fuse block on it with several other wires routed through the dash that seem to go in circles. I found that who ever wired up the tail lights did it by routing a trailer harness through the truck supplying power from a trailer power brake thing. It looks like I'm going to have to put another harness it it unless anyone could give me a better idea on how to eliminate the existing trailer brake setup. I'm not to familiar with those but I see it does have a brake line running to it as well. regardless, it doesn't seem I'll be driving this thing very son at all.

[73SWBBB]

scratch that last post. The trailer brake controller is now out and I'm back to the same issue. One of the previous posts stated there was a ground on the firewall specifically used for running lights. I believe i have a painless fuse block which has a harness coming out of the back with four wires which connect to a fitting that looks factory which also has four wires. I say it looks factory because it has a grommet on the connector which leads me to believe that it was once just mounted on the firewall. Moving forward i can find any other ground or wires other than those four leading back to the tail lights. So I'm now wondering if there are supposed to be only four wires, and if so which one is ground. Also I noticed the tail side markers don't work either. So I'm guessing its either the ground or power and those are shared. I guess I'm just keeping this post updated and periodically checking to see if there is anyone willing to assist.

[big bear]

is it a painless harness for sure ?   if so,  you could do a bit of research and look up the diagrams and such..  like find out how many circuit your kit is and maybe find part number and such.. painless is a very thorough company to deal with and very straight forward.

[beastie_3]

If its a painless, each wire should already be labeled every few inches.

[73SWBBB]

Figured it out. It is a painless and the harness is in great shape but the last time they painted the truck all the wires got painted with it. Long story short i removed all the bulb sockets and had to trace back and found a splice point that had both the sidemarker and running lights in common. The splice point had no power or ground. It was looped together and somehow forgotten about. A quick splice into the license plate power wire and she was good to go! I have a feeling this truck is going to commit to a love hate relationship with me. Thanks for the suggestions guys. Look forward to learning more in the future.

[bake74]

     Glad to hear that you got it going again.

[zieg85]

Welcome from NW Indiana

[Canadian 4X4]

Welcome!

[beastie_3]

Good find. We are all in a love/hate relationship.