Hello,I'm working on a 94 that has no TCC signal from the PCM going to the TCC solinoid (orange wire w/black stripe).The scan tool indicates that the TCC signal is "off" and not being switched.There are no codes and Overdrive works,TPS reads good,temp sensor reads good.I'm just wondering if anyone has ran into this issue before as I did search the forum and came up with no similar cases.Also the odd time the signal is there and then its gone.The truck has a BD Exhaust Brake,Pressure loc and Auto loc on it so without the TCC working this stuff is dead weight.I'm thinking the PCM is the problem but have never seen one fail before.Anyone else replace a pcm to resolve this issue?

Thanks

 

Does anyone know if the brake switch has anything to do with the TCC?

 

Yes the brake light switch will cancel TCC lockup. I would look at that first.

 

Thanks for the reply,I will look into that and report back when i see the truck again.

 

what exactly do you mean by brake switch

 

The switch under the dash that touches the brake pedal. It has a tendency to pop out of position or wear and cause all kinds of lockup problems with the TCC.