My Turn signals, windshield wipers & AC clutch all stopped working at the same time. I looked at a electrical diagram and noticed that they all run through GEM (control box ) or whatever they call it on the truck. That's where I got the idea about a bad GEM or computer. Any ideas?

 

Did it rain recently?

 

Generic Equipment Module (GEM) or Body Control Module is another term for it. Sounds like a the problem to me. These are getting very hard to find depending on your model and I don’t recommend getting one from a junkyard as water gets into many of those vehicles. There is a company that you can send your GEM into and they will refurbish it. Only problem is your truck is down for a few weeks until you get it back.

 

Try Rock auto first. I was able to buy a new/refurbished GEM for my truck. It will ask for your VIN
to verify if they have one for your application.

 

Neither the turn signals nor the A/C system rely on the GEM module (the wipers do). Don't know what diagrams you were looking at....