fireball

Hello all, I have a new wiring/electrical problem that I'm hoping someone can help me out with.

I just got done installing a new set of PIAA fog lights. They are 55W, and I reused the same wiring that my OEM Hella micro DEs were wired to.

The fog fuse blew twice yesterday. I checked the wiring tonight for a short and redid some of the connections, then put a new fuse in and everything seems to be working fine. Until.... whenever I turn the fog lights on, the gas gauge immediately goes to empty and the fuel light blinks.

If i turn the car off and restart it without the fogs on, the fuel gauge works fine. This seems crazy as I can't believe the fuel gauge is related to the fog lights. Perhaps I am crazy. I have a Haynes manual with moderately helpful wiring diagrams, which combined with my below-average electrical no-how does me absolutely no good.

Can someone please help?!

Thanks in advance!

Ritzy4Runner

iTrader: (1)

I took a look at the overall wiring diagram for my 1998 which is pretty similar to the 99 and can find nothing in common between the fuel gauge and the installed fog lights. Were these lights installed by the dealer or by yourself? I would check to see where the lights are getting their power from, what circuit and wire coloring which may give some light on why the two are interferring with each other. Basically the only thing that would be common between them would be ground.

If the lights are an after market install I would do some wire tracing to determine where they are getting their power from, connections to the operating switch and the ground path for the lights. I would venture a guess that the power proviced for operating the relay is some how crossed over int the fuel sender circuit. That would account for the loss of the fuel gauge when the lights are turned on. I hate chasing trons so good luck

fireball

Thanks for the info Ritzy. I wired them up myself.

I tied into the OEM wiring for the fog lights and am using the OEM switch on the stalk to the left of the steering wheel.

One thing that might be an issue - the PIAA connect had a black and white wire. The OEM fogs had a white wire/black stripe and a pink wire. I ran white to white/black and black to pink. Perhaps I got those backwards?

The fogs seem to work fine, but perhaps the wiring is backwards?

fireball

I think I sorted it out - swapping the wires on the fogs fixed the problem.

My 99 4R has a pink and a white/black wire running to the OEM fog connector. I incorrectly assumed the white was hot, when in fact the pink wire is the hot wire.

So the wiring should go PIAA white to OEM pink & PIAA black to OEM white/black stripe. The lights will work wired either way which was the confusing part, but I think when I had them backlights it was causing a faulty ground or something messing up the fuel gauge.

Now that all is correct and seems to be working, life is good again.

Ironmike4x4

I'm still curious to the fuel gauge issue. Unless there is a shared circuit somewhere to the fuel gauge or FL sensor or even a short to power to the fuel circuit. I have came across something similar on a vehicle where 2 wires at the BCM on an Impala were shorted to power causing some really interesting scenarios... took me a few days and many co-workers ducking flying wrenches to find the problem.