10-19-04, 11:57 AM
I've got a 1973 Coupe Deville with a heater/ac problem. When the selector lever is in the "auto" position the blower never blows on high speed, and it only sporadically blows on high when the selector lever is in the "high" position. The blower motor is new, I suspect the problem is in the control unit. Any help greatly appreciated!
10-19-04, 03:14 PM
Had that problem before on another car. Back then they used a seperate circuit for HIGH due to the voltage I guess. If you think the switch is alright, there is probably a HIGH BLOWER relay to check, and on my car the problem was an INLINE fuse (for high specifically) under the hood had blown. And once I put a new fuse in I was back in business. I think it blew again later, though, because there was a short due to a wire melting.
10-19-04, 07:43 PM
If I recall correctly, the blower relay bypasses the resistor and delivers power right to the fan on high. Does that sound right Piano?
10-20-04, 03:41 PM
I believe you are correct. It was using a lot of juice, that is for sure.
I know the other speeds were all on one circuit and then high speed had its own.
10-22-04, 04:55 PM
Thanks Barge and Piano, I'll check those things out and let you know what I find.
12-06-11, 11:55 PM
Hmm I have the opposite problem with my 1973 Fleetwood. The fan doesn't work at all on any setting except high.
My foggy memory recalls an orange? wire on the passenger side of the intake manifold with an in line fuse. ( I know Pontiac used it ) 30 AMP? We would cut out the fuse holder and replace it with 2 holders with 15 amp fuses. Another possibility is a hi blower relay up under the steering column on a strip of relays. The strip would melt after years of use, effectively disconnecting the relay from voltage. I know this was the set up around 76 thru 79. We would get a new hi speed relay and cut the wires out of the relay panel and connect them directly to the relay. Regarding no other speed except hi, I would suspect the blower resistor being faulty.