T/S Blinking Fast

This is not a "bad bulb" case.

My left blinker has been doing the strobe blink intermittently for a while, I found that if I pull down hard on the lever it blinks at a normal rate. Ok fine, buy a new combo switch.

Plugged in the new one and tried it, same issue although pulling it down hard doesn't slow the blinking.

Ok fine, there's a short to ground somewhere, removed all bulbs front and rear on L/S and when pulled to left turn position the flasher buzzes but doesn't click.

Ok fine, short to ground somewhere it is but here's the screwy part, after letting it buzz in the L/T position then returned to center position the RIGHT rear t/s light goes into strobe blink.

Anyone ever see this ?

Does the harness for the right side go up over the roof and down to the left side main harness or is it run under somewhere ?

What kinda vehicle ?

Tim_MN said:

What kinda vehicle ?

Click to expand...

My bad, 1998 Classic

Have you checked the lights when it is blinking fast to see if they are all working ? you have 2 lights in front and one in back on each side .

I had a 99 with this problem. I changed out all of the bulbs, just so I knew what I had to start with. Then I changed out the turn signal flasher, put in a heavy duty one. If I remember right, it was up under the drivers side of the dash

There are two types of flasher/blinker modues. One (thermal) uses the current through it caused by the lights to heat up a bi-metal strip that causes the relay to snap open until it cools, then close again and start the process. The other (electronic) uses a solid state module to provide the timing for the flash rate, not the current draw. These are commonly used when pulling a trailer so the additional draw caused by the trail will not make the lights flash faster.

It sounds like you have a thermal one and you have a short in the light circuit. Most commonly that is caused by a burned out bulb where the elements shorted on burn out. That is an easy fix, just replace the bulb. Sounds like you have already done that. The second most common short is actually in the socket for the bulb. If you pull the bulb and it keeps flashing, you definitely have a short, you just have to track it down by process of elimination. If you understand how an ohmmeter works, you can power everything down and measure the resistance to ground at various points around the circuit and find the lowest resistance, which should be close to the location of the short.

Another potential problem area is the tail light wire plugs and grounds behind the spare tire and plastic trim. Any water leaks from the side window or from holes in the fender can get water on the wires plugs. Some Cherokee also have relays located there. Inspect the wire. plugs, and clean/snug the grounds. Inspect any trailer towing wiring and suspect that any Bubba installed wiring has become faulty.



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