My son has a 98 Mustang that i am trying to help him with.

I noticed he didn't have any passenger side brake lights or passenger turn signals the other day, but did have one filiment of the bulbs going with the headlights. I changed all the bulbs (they looked good) and it didn't help. The brake lights and turn signal worked occationally, and we finally figured out what was going on.

Right side brake and turn signal lights will only work after using the left side turn signals, Then everything is fine. But once you use the right turn signal, the brake lights and turn signal do not work anymore on that side. That is until you use the left turn signal again, then everything is fine on the right side again until you use the right signal, then it's back to broke again.

This car has so many electrical problems that alot of things are screwed up. I'm not much for figuring out the electrical aspect of it, but we are checking the fuses and relays.

Where can i find a diagram of the 2 fuseboxes and what they control on the 98 mustang? I have tried a few searches without any luck. Google searchin show a few diagrams that didn't look right.

AS for finding out the gauge problems, i guess we will just look for a grounded wire harness somewhere.

 

I have been reading about a Smart Junction Box on the passenger side. Does anyone know if a 98 Mustang would have this?

What would it look like?

 

what type of mustang? v6-v8? Go through all the fuses, and the relays there maybe a cut wire, just troubleshoot.

 

It's a V6 model. We replaced 2 mini fuses but i don't think they had anything to do with the tail lights. All other fuses are good. The two relay boxes under the hood are for the horn relay and the starter relay.

After checking tonight, the brake lights would work most of the time, sometimes not when the headlights were off, sometimes it would. Right turn signals worked 80% of the time that they should have. I hate electrical problems.

Where would the turn signal wiring harness ground at? It's not near the turn signal assembly anywhere.

Does the 98 Mustang have a Smart Junction Box i could check?

 

On the brake pedal up under the dash there sould be a switch. Make sure that's ok and that the brake pedal wire isn't frayed.

 

Ok Tony, i will check that.


We plan on changing the turn signal flasher to see if that helps too. It works some of the time, but not all of the time. And also goes spastic occationally clicking very quickly. But i'm not sure if that could be caused by something else.

I always thought a flasher was either good or bad. No in between?

 

strange. something is wrong somewhere in the wiring, getting crossed somehow.
i once worked on an Olds Cutlass, everything went wrong with it. The fuel pump turned on from the headlight switch, the turn signals turned on with the brake, the dash lit up with the door switch, etc etc.

Turns out a single melted wire in a corner directional bulb had crossed paths with another wire in the harness, causing it all.