storer@GLOBE.UUCP (John Storer) (12/12/83)
I have been trying to locate the source of a problem on two cars. One is a 76 Camaro and the other is a 79 Lemans. Both have AC. The problem is that the fan (blower) does not operate in the high speed position. The problem existed when the Camaro was purchased, and it developed a few months ago on the Lemans. A GM mechanic suggested I test the high speed blower relay. Since I didn't think I had the necessary equipment to test the relays, I just replaced them on both cars. I didn't notice a relay for the other speeds on either car. That didn't work. I have replaced the switch on the Camaro, it was easy to get at, and the problem remains. The motor on the Lemans fan died , so that was replaced and the problem still exists there also. Any suggestions ? j. storer ..decvax!GLOBE!storer
wookie@alice.UUCP (12/14/83)
In reference to the blower speed problems: The multi speed bloweres are made by adding resistance in series with the motor. At the lower speed settings the curretnt draw is reasonable and so the motor is supplied directly from the blower speed switch and its associated circuitry (fuse in the fuse block). The high speed setting pulls on the order of 25 amps and so is generally supplied directly from the battery or alternator via a relay and a separate fuse usually located under the hood. Should this fuse blow the motor will still work at the lower speeds. Assuming the realsrelays are OK check the wiring to the battery or alternator and the associated fuse. If they check out then seek out the line which controls the relay. With a test light and some pieces of wire you should be able to track down the problem. I have had this problem on several cars and in almost every case the cause was the in line fuse under the hood. On my '65 POntiac the fuse holder had enough resistance to cause enough heating to melt the solder in the fuse rather than blow the fuse out. I tried so many different ways to stop the problem that I gave up and resolved not to use the high speed setting! Good luck....... If you need further help I have the complete repair manuals for the 78 Pontiacs and the 80 Firebird so I could help with the wiring diagrams. Keith Bauer White Tiger Racing
shacklet@ittral.UUCP (Captain Electron) (12/15/83)
I had a 74 Lemans with the same problem. It turned out to be a fuse located on a line coming from the alternator. If that's not it check the motor speed selector resistors located in the heater box. They are accessable by removing a small plate on top of the box under the hood. There is also a large diode on the same assembly; sometimes that opens or shorts and causes weird problems.(the diode looks like the kind in the alternator).