94 Corolla Electrical Problems/Integration Relay Help Needed

Hi, all.

I’ve got a 1994 Toyota Corolla DX with over 200k on it. Generally, it’s a good car. On a long trip (currently on it), I noticed that my cruise control stopped functioning when the headlights were on. Next, I saw that the breaklights were on, when the headlights were on. If the headlights are off, then the cruise control works and the dash lights go on when I use the breaks! There are not stuck breaks that I can tell. There are no blown fuses. I’ve replaced the break light switch and that didn’t matter.

So, after doing some reading, I think it’s the Integration Relay - essentially where many of the circuits come together and usually play nice with each other. It’s located on the lower left kick panel of the driver’s side. Supposedly, it’s attached to the backside of the fuse panel. But, after checking the Chilton’s (which didn’t show anything) and trying for a good hour, I can’t find a way to remove this panel.

I need help with good clear directions on how to remove the fuse panel!

Further, if anyone knows a source for used Toyota electrical parts, I’d be indebted. I’ve found new OEM Integration Relays for $189. I can’t find anything on ebay.

Of course, “break” lights are my way of spelling brake lights. “Measure once, cut twice,” I always say…

I assume that the brake light and tail light circuits are tied to a common bulb with two filaments inside it. Sometimes the filaments get crossed in the bulb and can cause this kind of trouble. You can usually visually see the problem in the bulb or you can try removing one side at a time and see if the trouble clears.

Wow. IF it’s as simple as that, I’ll be so happy!

I’ll give a shot tomorrow and report back.

Technicians are standing by.


I think that might have worked. I disconnected the right hand tail lights and it appears that things are working correctly. I’m going for a drive. If all seems well, I’ll look at all the bulbs and replace as needed.

I NEVER would have thought that one crossed wire could cause so much trouble.

I’ll let you know what I learn.

It is a fairly common problem. When the dash lights turn on with the brakes due to voltage backfeeding to the dash lights it is a pretty good chance that is the trouble. Trailer hitch problems are another source for that kind of thing to happen.

That fixed it!

I can’t believe a single faulty light bulb can cause all of these problems.

Thanks for all your help, Cougar.

Glad to hear you got things working ok. You’re welcome for the help and thanks for the update.