dadmetal15

Hello everyone,

It was time to join this forum since I've had my 05 F150 for a year now. Hoping I can pick some brains about some wiring questions. Yes, I have searched and the best I can see, my situation is a bit unique.

ok...

2005 F150. 5.4, automatic 4x4

bought truck used last summer. A/C DID work, but was unable to test 4x4 system. (my bad) After discovering 4x4 wasn't engaging (nor were any of the 4x4 dash indicators working), I started to troubleshoot the system and saw the transfer case motor was unplugged. I plugged the motor in and "bam", there goes fuze 11 and my air conditioning. Saw in the diagrams that fuze 11 is indeed the 4x4 solenoid and a/c clutch. Here's the kicker. The 4x4 system works. The transfer case motor engages in 4x4, but the hubs were hit or miss. 4x4 definitely works though and has been tested....still no dash indicator lights.....

Replaced relays to eliminate them, replaced fuse 11 and as soon as I turn on climate control, the fuse pops. The a/c compressor clutch gives me no visual evidence that it's spinning and I obviously have no a/c.

So....do I have an a/c compressor shot? I just replaced the 4x4 solenoid and for the first time, I saw dash indicator lights and did a little happy dance. Then I turned the a/c on and fuse pops again. I sometimes get a momentary dash indicator flash when I switch to 4h and I clearly hear the hubs engage and disengage. They did NOT do that before. I used to have to do the ford forward/reverse dance to get the transfer case out of 4x4 and I suspect the front hubs remained engaged constantly.

so that means although I have no dash indicator lights, the 4x4 system IS functional, but no indicator lights and no A/C.

Wouldn't the 4x4 system not engage if fuse 11 is blown? Why is the electronic 4x4 system working if fuse 11 keeps blowing?

I hate electrical. I was hoping to do some troubleshooting before taking it into the shop.

Thoughts?

ProjectSHO89

If you leave the transfer case motor unplugged, does Fuse f11 still blow when the A/C is turned back on?

BTW, the transfer case motor doesn't run off F11, only the IWE solenoid (in the 4x4 system) is on F11.

dadmetal15

Strangely, yes it does blow the fuse after I unplugged the transfer case motor..makes me scratch my head. How did this dealership (notoriously shady) manage to get the a/c working and I can't recreate it?

But to answer your question, with the transfer case motor unplugged yes, it does pop fuse 11 when I turn on climate controls.

And thanks for the tip about the t/c motor not being run off 11. Didn't know if it was in the circuit, even if not labeled. It's making more sense now that the t/c motor is out of the equation.

ProjectSHO89

You're going to need to do some electrical troubleshooting. Do you have a multimeter with a continuity beeper? If so, Ii can give you some simple checks to perform.