92 Silverado Blower & A/C not working:

[Joe D 92 Stepside]

Blower Fan not cutting on.
AC compressor not staying on.
All switches seem to be clicking.
Get "on indication" when ac button pressed: LED indicator for air conditioner in steady signal, no flashing signal showing malfunction. Appears that air conditioner is on but it is not staying engaged. Appears to try to engage, but kicks out quickly.

Checked and replaced "HTR-A/C" 25 amp fuse. Fuse tested good, but replaced just to be sure.

Replaced the resistor because it was old I figured I'd give it a shot: No Change - Blower Fan / AC still not working.

Bad fan motor or is another switch / relay possible culprit? Any other ideas??

Would like to eliminate options before replacing
Motor / Blower.

Any help appreciated, Just got my outboard motor running again and was ready to head to the Lake, and now this!

Thanks

 

[scott2093]

You could download the 92 wiring manual and look under the ac section until someone chimes in..

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[GoToGuy]

You replaced the blower resistor is it getting power from the relay? Compressor starting and stopping quicky is one indication of low freon charge, it may have minimum pressure but a low 134 charge. Two separate problems, fan and 134 issue by checking with a set of HVAC gauges.

 

[Schurkey]

'92 would be R12 originally. Potentially converted to something else, like R134a.

Blower fan problem, and A/C compressor problem are likely not related.

Is the blower fan getting power? When my '97 K2500 blower fan didn't run, the 60 amp maxi-fuse was blown, the smaller (25 amp?) fuse was blown, the thermal limiter on the blower resistor assembly was popped, and the blower motor was so fried that when I fixed everything else...I got the blower motor to run which flooded the interior with smoke as the motor 'bout caught fire. Best guess is that the blower motor drew excessive current, which popped all three protection devices "upstream".

The A/C compressor won't run if the refrigerant charge is low. Turn on the A/C at the dash control head. Temporarily jumper the connector at the low-pressure cutout switch. Compressor run? Don't let it run long as without refrigerant, there's also no lube.

There's also issues with rotted wiring/wire harness connections that reduce power to the A/C compressor clutch. Voltage gets low enough, the clutch won't engage ESPECIALLY if the compressor clutch gap is excessive.

 

[Joe D 92 Stepside]

Thanks so much to all!
Not sure of another fuse to check other than the "HTR-A/C" 25 amp fuse already mentioned???
I think the AC is ok after further checking.
Going to check the leads to the blower and if good will hook the blower up to my boat battery to see if its good. Probably replace it either way - does seem like fan was blowing less over last several years and its probably original.
If still No Go - I'm gonna take it to my favorite "real" mechanic and write a check. Thanks again for the help and Merry Christmas to all!!!

 

[Joe D 92 Stepside]

UPDATE: All systems GO!! After moving stuff to get to blower motor I noticed the purple lead had come off the prong! Pretty sure it came loose when a fishing buddy accidently kicked the blower shroud / cover. Not a lot of leg room and he's a big dude. I had noticed the shroud was a little out of place.
Pretty easy fix, an early Christmas gift!!

 

[GoToGuy]

Fan runs, can hear higher speeds, still feel like less airflow?
Remove fan use small mirror to see how much fuzz, hair, leaves, other crud is is packed up against exchanger fins acting like an air filter reducing air flow. One thing that can be a low flow problem.

 

[Joe D 92 Stepside]

Seems to be better, maybe new resistor helped. Thanks again to all for the tips.