I have an 04 Screw Lariat 4x4. The display for the a/c heat is showing a 3 digit number that cycles seemingly between 103 and 126. The auto light switch lights up then the defrost/rear defrost light switches light up, it cycles between these switches showing the 3 digit number between the cycle. When I press a button on the controls it has EXT above a 3 digit number. There is also a constant clicking coming from around where the fuse panel is. Any info would be greatly appreciated.

 

I hate electrical problems.

The clicking would be a relay. You can get a relay tested, but they're usually cheap enough that a replacement makes sense, especially as the truck gets older. You can also look at all the connectors in the circuit. That's a bit tedious, tracing down the wires and looking for corrosion.

Probably the worst case is that the climate unit itself is bad, shorted out and drawing too much current, overheating the relay, causing it to activate and deactivate constantly.

I'm sure there are other possibilities, too. Let us know what you find.

 

Pulled the unit out, unplugged it for a couple if minutes plugged it back in and now it works fine. I don't know why it did what it did.

 

Is your battery in good shape? A weak/about to fail battery will cause all sorts of weird electrical issues.

 

Weird, but I know what you mean.

My AC was working fine Tuesday, but Wednesday was even hotter and the AC didn't blow cold at all. On Thursday I took it to the shop, but for them, it blew cold all day. Worked again today, too.

Ford gremlins!

 

I will have to test it. Seems ok but I can't answer for sure.