Electrical circuit question

[Ryan S.]

Everytime I think that I got the short located, it turns out I don't. I do know that it is in circuit C as shown in the electrical supplement. I think that it my be in my trailer brake controller connections, which include the stoplights on circuit C. My question is, if I disconnect power to the controller, would it eliminate the short if it is in the stoplight connection? The short occurs even though I am not using the brakes and therefore no power is going through the brake switch. I have spent hours tearing into my dash and every else I can get to wires, and don't know what else to do. On the positive side, I cleaned out the inside of my dash and inside of the rear quarters. 23 years of gunk and dust is now gone.

 

[lovetoski]

Many Toyota switches are ground switched, that is, it's the ground side that's switched not the hot side. Your logic is right, but the truck is backwords!

Also, trailer connections are known for going bad. Lots' of corrosion/crap back there, and sometimes they're installed on the cheap.

I think you are on the right track. Disconnecting the power to the controller is simple, and could help you to home in on the problem. Be prepared for eleminating or replacing the trailer connector.

If you do have to rewire back there, solder and good heat shrink. No cheapo heat shrink from Shucks. Napa (ask for their best stuff) or a marine supplier.

 

[Mike S]

Doug is correct. Trailer wiring causes all kinds of mystery electrical headaches. I would disconnect the whole mess, then test the circuits. If this fixes the problem, I would then tackle rewiring the trailer connection. If the average trailer shop or PO did the work, it could well be screwed up.

M

 

[Ryan S.]

Disconnected the controllere last night just to see what would happen. The result was that all of circuit C that I could see, was dead. Somehow the power for circuit C starts at the controller connection. What's more, is that as I was hooking the splice to the connector back together, the wire it was spliced too-a 10 ga wire from the + terminal of the batt. to the alternator-came loose from the back of the alternator. I replaced the connector from the 10 ga. wire to the alternator and two trips later, no short. Funny if that was the problem the whole time. I tore my truck apart and the short was in the easiest wire to get at.

 

[lovetoski]

I'm glad you found the source of the problem. Props for stickin in there to find it.

However I am a little worried about your description of how and where the controller wire is connected. The controller is powered directly by the alt/batt...but is there a fuze between the + and the controller? If not, then the entire circut C might be unprotected.

 

[Tinker]

Best trailer light hookup I ever made used a relay & fuse for each circuit. The relays were activated by the brake, turn, & backup lights (have those on my trailer). Switched the ground so the relays only worked when you wanted them to. Ran clean power from the batt to the relays. Shorts in the trailer circuits only blew the fuses.

Painless has something close, but with 8 circuits IIRC. Probably cheaper in the long run than modifying a car fuse/relay box like I did.

 

[Ryan S.]

However I am a little worried about your description of how and where the controller wire is connected. The controller is powered directly by the alt/batt...but is there a fuze between the + and the controller? If not, then the entire circut C might be unprotected.

The power runs through what I think are called automatic reset circuit breakers. The installers attcahed them to my wiper arm access panel on the drivers side. I had them do the install to save me time, but in the end I've got about 10 hrs looking for a short and a circuit breaker in a stupid spot. Last time I try to save time by having someone else do the work.