Brake light issue

[MJRemi]

I noticed my brake lights were intermittent the other night when i was backing into my driveway. They came on/off as I applied constant pressure. Now they don't come on at all.

My hazards work fine and all my fuses are OK. I cleaned the contacts on the brake pedal switch but no effect.

Bad switch?

Loose wire? Bulbs and connectors would prevent hazards from working, right?

[jimoshel]

First thing I would check would be the brake switch. Make sure it hasn't worked loose or is broken.

[MJRemi]

First thing I would check would be the brake switch. Make sure it hasn't worked loose or is broken.

 

It didn't appear to be either and I cleaned the contact prongs. I just finished checking and cleaning every tail light connector and all seems OK. I will try swapping the pedal switch out for one I have on the bench from a 86. If that doesn't do it then I'm baffled because all the other lighting functions work.

[Akula69]

My experience was very similar...all the brake functions worked but the brake lights would not. I went through all the steps and found that the culprit was the push rod on the booster.

 

I had done the brake booster upgrade several months ago and ground the rod down to allow the use of the old brake light switch. It worked fine until just a few weeks ago when I noted they were not coming on. As I studied the switch, I noticed it had shifted up slightly on the pushrod, and the contact plate was no longer able to release. When I rotated it back down slightly it immediately worked again.

 

I could not find a way to resolve the issue, so I switched to the 93 - up brake switch.

[MJRemi]

I'm swapping my booster for a ZJ booster in about 4 weeks. Looking at it, I don't understand how the ZJ rod can function exactly like the MJ rod, even if cut flat. The MJ rod is a bit lower on the pedal. I'm going to cut the two rods and weld the MJ rod onto the ZJ booster so I don't change any angles or heights.

[Boots]

Mine did something similar to that, I cleaned all the plugs and it still wouldn't work, so I gave up. A couple days later I was looking at it again and one of the wires going into the plug under the very back corner of the bed was just a little bit loose. I jammed it back in really good and they have worked fine since.

[MJRemi]

Well, I couldn't get the original switch off. The nut just started rounding off so I cleaned the switch in place and wiggled it around a little to re-align. The brake lights come on but only with a fair amount of pressure. A light touch to the pedal will not activate the brake lights so I will swap out the switch when I install the ZJ booster. ( hacksaw the switch bolt )