2006 Silverado CrewCab LT3 blowing 10 amp AC fuse when starting

[richtersrodz]

I've been searching and searching the forum and haven't found my exact issue. My 2006 started blowing hot air only. 10 amp fuse blows immediately upon starting the truck. BUT, not when the key is on, and cycling through all of the AC functions. I have replaced the AC clutch (not the compressor), replaced the digital AC head unit in the dash, and just last night took the dash apart to replace the air actuator that is on the top of the unit, inside the middle dash (behind and below the radio head unit), because it was not blowing outside of the passengers side vents (didn't fix air flow problem, replacing another actuator today). I have also swapped my relay with the washer pump relay to verify that works. The 10 amp fuse (verified with test light) stays on, until I fully turn the key, to start the engine. Immediately upon starting, it blows the fuse. This happens even when I unplug the electrical connection to the compressor. Has anyone come across this issue? 

Edited June 6, 2022 by richtersrodz

[richtersrodz]

I will also mention, I have also unplugged the low pressure switch and shorted it with a wire, and unplugged the electrical connection to the new AC clutch. 10 amp fuse still blows when I start the engine.

[richtersrodz]

Update.. just so this might help someone else. I had pulled the bottom actuator from the center floor board last night, and while plugged in, turned on the key. This caused the actuator to turn all the way to the right, and go past the slotted run mark. This caused me not to be able to reinstall it. Searching youtube, and I found guys that said to replace the motor now, because you ruined it. I was on my way out the door, and decided to do one more search and found a manual reset of the motor with a 9v battery. If you put the hot + 9v lead wire on the last post (stud 5) and then apply the - 9v terminal to studs #6 and #7 (the next 2 over) it causes the motor to run backwards in the opposite direction, and returns the key to within the clocked positions. If you touch just #6, it causes it turn the other direction. I immediately saved myself another $60. Now I'm back to my original problem.. 

 

youtube.com/watch?v=vWBGKfl7k24&t=9s

 

Start at 1:08

 

Edited June 8, 2022 by richtersrodz

[richtersrodz]

Just tried..

Replaced 10 amp with a 15 amp fuse

Pulled out and inspected other HVAC fuse, to the right of 10 amp. 

Turned on key to accessory position  (not started)

Watched digital head unit reset and cycle through it's functions

Turned off cold function button, * that engages clutch

Turned off AC completely. All digital output off.

Test light shows light on 15 amp fuse

Turn key to start engine (light shows good while cranking)

As soon as engine starts.. test light goes out, fuse blown

 

[richard wysong]

time to get a wiring diagram and see exactly what the fuse powers

[richard wysong]

does it blow with the relay pulled? check the wires to the compressor., did they get pinched when you did the clutch?. varmint damage? ETC

[richtersrodz]

I went out today, and unplugged the compressor wire harness. Cranked on the truck, and the fuse blew again. So I looked up what wire I would need to put on the battery, to manually engage the compressor. According to people that have done this previously, and reading the wiring diagram on the side of the AC relay, I used a wire and alligator clip to charge terminal #87 on the compressor relay. (see pics)  Before doing this, I first unplugged the relay totally, replaced the 10 amp fuse, and started the truck. Wow! No blown fuse! So that means it's something with the relay circuit. With the truck running, I jumpered the positive battery terminal to the #87 slot in the box for the AC compressor, and instantly my wire started smoking and sparked. So I have a short going from the relay, to the compressor clutch wires. So, my search continues, but now a bit more focused, and at least now I know what I am looking for.  

[richtersrodz]

Thanks Richard.. I think that got me started in the direction I needed to go!  I'll keep searching and post my next findings.

 

Judd

 

[richtersrodz]

Well.. happy to say that I found my issue. Sad to say, that it took me so long to see it, right in front of me. It was a bundle of wires that run right down next to the alternator, and the loom had crumbled due to heat, and being 16 years old, and was rubbing on a hard line. I only saw it after I was laying on my back, tracing the wires back from the compressor, around the front of the engine and going upwards, towards the battery..  SO..  1 resistor pack and new blower fan under the dash, 1 digital AC head unit, 1 AC clutch, 1 air actuator, 30+ fuses, and many, many weeks later, I find the wire short.  I'm just glad I found it before I put it into the shop. You can see from the pic where it was rubbing the power steering line. 

 

[richard wysong]

 good job!

[dna9656]

P-E-R-S-E-V-E-R-A-N-C-E  

 

You got it in SPADES! Congratulations!

 

Edited June 7, 2022 by dna9656