Posted by Ron Bass on July 29, 1998 at 00:42:19:
In Reply to: Re: aux fan not working posted by Peter Florance on July 24, 1998 at 06:36:56:
: : Peter: what you're describing is making sense. I'll try tracing the wires this weekend. I would think that if I apply voltage to the red wire from the relay to the fan and ground the brown wire, the fan should work (if the motor itself isn't blown). I presume that the relay for the fan is located in the same general area as the fuse box. Please let me know if I'm wrong. Thanks again for the info - I'll let you know how it works out. Ron Bass
: I think the relay is in the front of the fuse box above the battery (My Haynes manual shows a round relay, but I would have thought square). My system was hacked in when federalized in 1984. So I can't tell by mine. Maybe someone with 77 E-12 can tell us where it should be?
: I always like to trace the existing voltage (or lack of) rather than applying my own unless I know the wires and the device are ok. If you do apply votage, get an extra fuse holder and make a jumper out of it to apply the 12V. Put a 25 amp fuse in it so if you have any severe short you're covered. In either event I keep a fire extinquisher handy ANY time I work on the car - these cars are that old! )-:
: I got these needle sharp meter probes that allowed me to poke tiny holes in insulation w/out damaging wire. Made it convenient to trace out wires.
: I'll bet that you'll have +12V on red but the ground point is probably bad contact. If you got +12 on brown, it's not grounded! If your're missing +12 on Green/Red into relay, work back towards fuse box (fuse #17?). The fuse boxes were famous for melting at the fuse holder.
: I took mine and cut out (Dremel tool) the old holder for heater/interior A/C fan and expoxied in ATO (blade type) fuse holder. Looked good and worked great!
: Peter
Peter: thanks for the info. Turns out that the relay was bad. It was clicking when the AC was turned on and off, making me think that it was working. However, I checked it with my meter, and found 12 volts going into the relay Green/Red wire, and 0 volts going out. $8 for a new relay, and the fan is now working when the AC comes on - a real easy fix (the AC is also alot cooler now). I've also gone out and purchased a Haynes manual. Next time I run into this tiype of problem, I'll have a schematic to rely on. Thanks again for your help! Ron.