troy paulekas

There is something wrong with my tail light circuit. I have no dash lights, no tail lights, no brake lights. Head lights and turn signals work fine.
I have searched this issue, however any solution I found wasn't dealing with not having any power to the circuit at all.
The 15a tail fuse is fine, the tail light relay is fine, but there is no power to the tail light relay.
My fuseable link is fine, and everything seems to be okay coming off the fuse box in the engine compartment.

scope103

The taillight relay is before the taillight fuse. The power to the relay (pin 2) comes straight from the 80A ALT fuse, so if you don't have power TO the relay you've got a wiring problem somewhere.

Be sure you're measuring the right pin; pin 3 is to the fuse and then to the lights. Pin 1 goes to the switch; grounding pin 1 should close the relay and light the lights.

troy paulekas

So, I have power coming from the white wire that comes off the 80A as tested right after the fuse box. I have no power when I test the white wire that plugs via harness, directly below the tail relay, into the kick panel box. Is this the wire that hooks up to pin 2 on the relay plug-in?

troy paulekas

http://cimg8.ibsrv.net/gimg/www.yota...4e2b0f7363.jpg

Here is a picture I found: The white wire that is covering the tail relay from view...in my truck, this wire has no power in it.

wyoming9

iTrader: (1)

Just what are you working on??

Since no fuses are open and your truck has not burned you most likely have a poor connection .

A corroded or bent pin can happen so easy.

A poor ground

Has this ever worked??

scope103

The brake lights don't work on the taillight relay, but they do get power from the white wire you are referring to (the white wire ends in pin 8, the upper most, of the connector in the middle of "J/B 1" (the kick panel fuse box). Then to pin 2 of the taillight relay.) Is the heater fan out too? It isn't powered through the fuse box, but through the same white wire.

That white wire is spliced to the yellow wire from the 80A fuse in side the harness on the right side of the engine bay. My guess is that splice opened up. I'm not brave enough to unwrap a long bundle like that (though you might see a point of obvious damage, and that will narrow it down). You might be able to carefully bypass that wire from the 80a fuse to the connector on the fuse panel (but check the heater fan first; if that is also not working, bypassing now requires two wires).

wyoming9

iTrader: (1)

Perhaps it would have been better stated The Brake lights don`t work off the Tail light relay in the stock configuration !!

I rule nothing out when it comes to wiring improvements.

That old tape in a major pain to get off.

Just_ Rollin'

Just dealt with this, check the integration relay.

troy paulekas

Integration relay? Does this just refer to the drivers side kick panel fuse box?

troy paulekas

http://www.ebay.com/itm/Toyota-4Runner-1989-1995-Relay-Integration-Box-Module-Computer-ECU-82641-89102/331260416327?_trksid=p2054897.c100204.m3164&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140407115239%26meid%3Dc353271190484713b3a58bde4d388f42%26pid%3D100204%26rk%3D7%26rkt%3D17%26sd%3D231483618701
...this guy huh?

scope103

For what? I've never taken this apart, but my schematics show that some of the output of the taillight relay goes through the integration relay. So if the relay is working but the taillights are not, that's a good place to look.

But Troy says that he has no power on the white wire (pin 8), which also explains why the relay is not working.

troy paulekas

I should have included a bit more history....
about a year ago, my heater fan stopped working, no power was coming in. According to the diagram I included, I cut the wire going to the taillight circuit where it comes out of the eng. comp. fuse box and bypassed it by running it straight to my heater circuit, leaving the wire that (from the diagram, goes to the taillight circuit) just sitting there w/o power. My heater then worked and the only thing that changed anywhere else was the my ebrake/checkengine lights stay on all the time...the taillights and dash lights still worked fine. I didn't bother to mess with it since I was under the impression the only thing this wire was doing was feeing the heater....I don't understand why the tail circuit stopped working then, but it didnt.
Yesterday, I resupplied that wire with power, my checkengine/brake lights go off, but the tail circuit is still w/o power.
This integration relay sounds like it might be the answer, where is it located? I can only find information that says 4runners have this integration relay...not pickups. Does my 89 pu have one?http://snjschmidt.com/wiring/power_source.jpg

scope103

The integration relay plugs into the back of J/B 1. http://personal.utulsa.edu/~nathan-b.../4lighting.pdf

Did resupplying "the wire" with power give you power at the white wire on J/B 1? To the taillight relay?

troy paulekas

Nope. It still has no power. Beyond that manouver it is stock wiring.

troy paulekas

So..from the diagram you sent...if there was something wrong with just the integration relay..I should still be getting power to the tail relay. True?

scope103

The wire from the 80A fuse is supposed to go to both the heater motor and on to be the "white wire" you've referred to at J/B 1. I can't explain why your taillights continued to work after you cut the wire, bypassing only to the heater motor. Perhaps your bypass powered the heater motor and "onto" the taillight circuit, but since then something has broken downstream of the heater motor. At this point, what is important is that you've confirmed you don't have power to the "white wire" that supplies the taillight circuit.

(My schematics show the integration relay has nothing to do with the white wire, but obviously your truck has been modified).

Why don't you just jumper 12v to the white wire (at J/B 1, not the engine compartment) and see what happens? If you're afraid of blowing a fuse somewhere (always smart when probing with 12v), consider using a "test light" to put some resistance into the circuit. I'm going to guess with the test light in the circuit you won't be able to get enough current to close the relay, but you might be able to hear it trying to close. Then, just try straight 12v.

The "best" solution would be to figure out why the heater went out; I'm guessing you have a damaged wire somewhere that is just slowly getting worse. But since you've already bypassed to get the heater working, continuing with the rest of the circuits supplied by the damaged wire wouldn't be so bad.

scope103

True (according to the schematics --- you may have more wiring modifications than I know of).

troy paulekas

Sweet...I jumper jb1 and everything on the circuit now works. Feels good to hear the click of the tail relay again, thank you.

scope103

Your "white" wire is broken/breaking. You cut it at the 80A fuse (good idea), but depending on how you wired up the heater fan and your newest bypass, that wire might be getting "back-fed." If it moves around enough to contact the frame, you'll get a big spark! If the fuse protecting the wires to the heater fan and the taillights is the same 80A fuse, once it blows everything shuts down.

You might want to look at the engine-cowl wire on the right to see if you can see obvious damage. You might think about how you're hooking up your bypasses to reduce the chance of back-feeding the "bad" wire.

troy paulekas

I'm going to try to get everything back to stock and rewire everything..but not until this summer when I gave time and space. I don't see anything obvious..hopefully it will be okay till then.
one more problem. When I brake..left tail light works..right only half way. With my running lights on when I brake..left side works..right side not at all...?