Starter not working after replacing A/C controller

[coryforsenate]

Hi all, many thanks in advance for your replies.

'96 C1500 5.7l Silverado 350cc, extended cab, 4l60e

Yesterday my fan quit working. The highest setting had been out for a while but the other 3 levels worked fine so I just left it alone. I replaced it six years ago with an OEM. Can't seem to find an OEM one anymore so the new one currently installed is a Dorman.

So, I had started up my truck and as I was backing out of my garage I noticed none of the fan power levels worked. I pulled back into my garage and pulled out the controller. Got the new one and swapped it in. Now the starter isn't working at all (no clicks) and the fan still isn't working, which I'm not sure if the new controller is bad (the controller lights and the vent flaps work) or if while swapping it I pulled out a ground wire or did something to the relay switch wires or something else. Battery has been checked and is fully charged. The relay switch is about 2 years old, had what I thought was a totally dead starter back then but when I pulled the relay switch out and checked it with my voltmeter it was bad.

I'm guessing it's an electrical problem, either a bad ground, the ignition cylinder, the relay switch, or something else. Since electrical stuff can be a huge headache to figure out, any suggestions for what to check first is super appreciated. I've got a voltmeter and all sorts of tools. I'm reasonably handy, I do all my own work and rebuilt my transmission. I'm just not very experienced with chasing down electrical problems. Oh, and scanned it, there are no codes.

What still works
Dash lights, including on a/c controller
The noise when your partially turn your key but seatbelt is unbuckled
Headlights
Radio and CD player
The flappers that direct airflow to your feet vs face
Fuel pump
Battery is fully charged
I checked a lot of the fuses and moved around the relay switches in the engine bay and they all seem fine. I haven't checked every single fuse

Not Working
Starter, no clicks or anything
Fan

Ask me any questions, I'll be regularly checking this thread. And again, many thanks!!!

 

[kennythewelder]

Your starter has nothing to do with your HVAC fan. Iif the starter is not working, then pull it off , and try it off of the truck. If you dont know how to jump test it, then bring it to your local parts store. They will test it for you for free. As for the HVAC fan, that sounds like the resistor. This is on top of the HVAC box where the heater core, and a AC evap core are. There are a ton of videos on this job on you tube. Y T search c1500 AC resistor replacement.

 

[coryforsenate]

So it may just be a coincidence that the starter quit working when I replaced the a/c controller? I haven't found the right wiring diagram yet but was wondering if the ignition switch, in addition to the starter, controls the blower motor.

I replaced the resistor around 4 years ago but parts these days, it could easily have died already. I went ahead and ordered a new one and it'll be here Tuesday. An OEM one is cheap enough ($15) that I'm not worried if I replace a part that's actually working.

 

[coryforsenate]

Let me find a piece of wire to test the test the starter via the starter relay switch first to see if it spins. I'd much prefer to not have to pull it out. It's the old non-gear reduction style so it's a big a$$ one and a pain to pull out.

 

[stutaeng]

What always works for me is a test light with those alligator jumper cables. Go underneath and hook a test lead to the starter solenoid and hook up the test light near your windshield where you can see it and then to ground.


Now go inside your cab and crank and see if the test light lights up.

 

[coryforsenate]

UPDATE UPDATE UPDATE UPDATE UPDATE

Starter works. I used a piece of wire to connect 30 and 87 at the starter relay connection on the fuse box and it spun as normal.

So there's something wrong between turning the key but before the starter relay switch.

Suggestions for the next troubleshooting are welcome. It's raging hot here right now so once the sun goes down I'll probably pull off the ignition switch under the steering wheel to test it with my voltmeter.

To update the "what currently is working"

What still works
Dash lights, including on a/c controller
The noise when your partially turn your key but seatbelt is unbuckled
Headlights
Radio and CD player
The flappers that direct airflow to your feet vs face
Fuel pump
Battery is fully charged
I checked a lot of the fuses and moved around the relay switches in the engine bay and they all seem fine. I haven't checked every single fuse
NEW---Starter turns over when it's jumped at the relay switch in the fuse box

I feel the "what works" is key info to figure out where the problem is but electrical diagrams look like a foreign language to me.

 

[coryforsenate]

Quick question, can I turn the key to "on" and jump the starter and drive my truck as normal?

 

[kennythewelder]

Quick question, can I turn the key to "on" and jump the starter and drive my truck as normal?

You should be able to. Give it a try.

 

[coryforsenate]

Did the wire at the starter relay in the fuse box trick with the key turned to have the fuel pump running. Engine turned on just fine, drove around just fine, went to get groceries, did the trick again, came home and parked it. No codes showed up or anything abnormal other than the blower motor not working, everything was normal.

I went ahead and replaced the starter relay switch in the fuse box on a whim, did not solve the problem.

Based on this, does it seem like the ignition switch may be the problem? I don't think there's too many other possibilities other than maybe something like a wire in the dash got yanked when I was replacing the a/c controller and isn't grounded or something. I think the ignition cylinder can cause problems starting the truck too...

Waiting for my garage to cool down more and then I'll pull the ignition switch to test it with my voltmeter unless someone has a suggestion.


Are there any relay switches/fuses under the dash that I should be checking? I know there's some but I don't remember what they are. All of the fuses in the little box between the window and the driver side dash are intact.

 

[Armalite15]

Sounds like the ignition switch. Had an appointment a few weeks ago, drove the truck no issues got done went out to leave, no crank. I was around 179000 miles at that point. Ignition switch failed instantly no prior warning or issues. Really easy to check though you can plug the new switch in and make sure before you even pull the old one. I’ve owned a lot of these trucks but that’s the first one I ever had fail. I used a Standard ignition replacement, I’ve always had good service with them.