1970 Olds 442 - Blower Motor Works in all Speeds Including High when Moving from Off to Heat, Defrost & Vent, As soon as Control Reaches Normal A/C the A/C Heater Fuse will blow under dash. Any Help will be Appreciated.

 

Perhaps there is an issue with the AC clutch? Try unplugging the harness from the clutch and see if the fuse stops blowing.

 

I just got threw unplugging wires at the A/C Clutch Relay Still Blowing the Fuse

 

There are three switches on the A/C control panel...The left one turns on the compressor, when the lever gets over to the right, and the middle one puts power (two brown wires) on the third one, the fan speed switch. You must have a short in the wiring on or near the back of the control panel. Or possibly where the wiring passes through the firewall behind the distributor.

 

Will begin looking for short tomorrow after work - Thanks to all

 

The CSM says that there is compressor hold-in relay (on fender filler) which probably should also be checked. Look for brown & dark green wires. Let us know the solution.

 

Ok, you have not followed my diagnostics for shorts that I mentioned over on 442.com a few days ago!

OK someone mentioned a/c relay on the passenger fender. I used those same directions I gave you before. When I found my short I had bumped the cover sideways on my relay just enough to short against the coil while working on something else.

Not saying that the relay or wiring is not the cause, but mine did the following: no matter what setting as long as the fan was on, when you turned the key to power up the car it would blow.

If you use the meter as prescribed, there will be no need to purchase a hand full of 25 amp fuses.

Pat

 

Finally got to get back to looking for short - Found short in Green Single Hot Wire That Plugs into A/C Relay - Thanks to All !!

 

Super job! Glad you founder the bugger.

Pat