I think I know the issue but I'm no wiring guy. As title states, my cluster illumination lights up with my brake lights. I do have on tail light out that when swapped for a known good bulb still doesn't illuminate. So my problem would be in my brake light circuit somewhere. Is it a ground issue or could this be a short somewhere?

 

is it the right bulb for that slot?

 

i have s4 tails and used one of my other working bulbs from another brake light. worked in the good slot before and after I tried in the dead slot. not sure why it causes my cluster illumination to come on with brake lights though.

 

Your car has sat in a field.. I'd be concerned mice have chewed on some things that shouldn't have.

Obviously tho, you should inspect your wiring and your grounds. This would be a Longshot here, but maybe disconnect your headlight switch and see if the problem persists?

 

Not to thread hijack, but my car does something similar after I replaced the bulbs with LEDs.

I replaced the rear bulbs (brake, signal, parking) with generic LED drop in replacements from eBay. Temporary until I get all of my red, yellow, and white LEDs in the mail and perform a proper conversion.

Modified my flasher module to delete the fast-blink warning (replaced resistor R1 with 1 megohm).

Now, when I am signaling and my foot is on the brake, my dimmer circuit activates whenever the signal flashes (on, off, on, off). Does not occur when signaling if my foot is off the brake, or if my foot is on the brake but without signaling.

I'm not looking for a fix, as it does not bother me and my current setup is temporary, but I thought I would contribute that as it is similar to your problem.

 

And regarding the bulbs, some bulbs (1197 I think) are dual element and others (1196) are single element. You can check by taking out each bulb and comparing the base of the bulb to the socket. If the socket has one terminal (not including ground) then of course if is for a bulb with one terminal, and vice-versa.

 

One good way to find out is remove the bulb you just replaced and step on the brakes.
If the cluster doesn't light up then you got the Wrong bulb in there.

 

Its not the bulbs, I have the correct bulbs in my other 3 tail lights. This actually started before I put the car away but only one of the lights is doing it. Just never fixed it since I still had one brake light working on that side. I'll be going through the car fixing many things in a month or so after I finish my daily. I was just wondering if it was a ground or short issue and why it would be activating my cluster lights. I really hope its not my headlight switch, I replaced it a couple years ago but it has been sitting for a while.

Collin, jz swap is dead. I'll probably be rebuilding the na this summer but the chassis restoration is first. I'm going to build a pole barn to keep the FC under while I fix things and weld so its out of the rain and I can keep it on blocks. It will be painted too this year.