stupid electrical!

Both of the Mazdas have one of the running lights on the tail light out. All the other lights work fine. Bulb is good.

Seems to be a grounding problem, as the signals and brakes will flash when the signal is on etc on the black reg cab, but on the ext cab, just the running light is out.

Can't seem to source the problem of the wacky tail lights or non functioning running lights. Any insight other than cleaning the grounds?

Best suggestion I can offer is go to the connector between the tail light harness and the cab harness and use a test light to verify you are getting a good signal to that point. The connector is located on the passenger side of the back wall (standard cab). I don't have the wiring diagram at the moment to tell you which color wire is which but there should only be 5 or 6 wires in the harness.

If everything tests out good there, then it's just a matter of finding the break / bad spot in the tail light harness.

i had this for awhile and couldnt figure it out. the bulb looked fine. you could go to the housing and just pop it with your fist one time and bam the light would work. Turns out the bulbs filliment was broken just bad enough that a jar would make it go out but physically it looked perfectly fine.






-justin

hmmm weird. On th eblack truck we have power going right to the bulb, but it doesnt work.

Havent even tried anything on the ext cab, but it had a trailer harness spliced into it and the harness is all hacked up and ugly.

Actually, the wiring is pretty ugly on both trucks. On the reg cab, the gauge cluster light comes on with the key.

ive noticed that my ol 88 and current 86 had the trailer connectors and was a mess so removed it..

i also had problems with my tails in my 88.. but it was just a bad socket. like the + (pos) which is inside was a lil rusty so i cleaned em and walla they worked.

On Kermit and my grey truck I just had dirty grounds on the frame and on the tail light harnesses. Cleaned them up and it was fine. This time, no luck so far. It's getting really annoying driving around here at night because we're waiting to get pinched for a fix it ticket and whatever else they decide to throw at us if we get stopped.

wow,so it only took me a month to fix the problem.

I got a harness from the cab back from a 91 ext cab with a carb and ABS. I plugged it in and my tail lights just went haywire. I'd hit the brakes and my reverse lights would come on, no running lights at all, my brake lights would flash as my 4 ways and my right signal would work, but made both brake lights flash.

Figured out that the pins on the harness needed to be moved around to match those from the existing harness from the truck. Got all that figured out and plugged it in and everything worked on the first try. And now I also have all the wiring for ABS, which my truck doesn't have.