I followed the wiring diagram for the dash harness from the "72 Cutlass/442 assembly manual and I find that my fan switch on the heater controls turns the fan on and off whether or not the key is even in the car. Not a big deal but I believe the open circuit slowly drains my battery. I removed the fuse in the heater/AC spot on the fusebox and the fan is still able to be turned off and on by the fan speed control switch. Anybody have any thoughts on where I may have made a mistake? I've seen some videos on how to find a battery draw by disconnecting the hot on the battery and placing a multimeter into the line feed but the videos suggest pulling each fuse until you identify the draw. Not sure that would work in this case.

 

Does this car have heat only or does it also have AC? The wiring and controls are a bit different between the two.

 

Hello again Ken, heat only. A suggestion was to replace the blower relay so I ordered one today since it is an inexpensive part. Now I'm having quite a time trying to locate the relay on the car. Wondering if it's under the dash on top of the blower box/heater core? I remember plugging in some wires there but my assembly manual only shows a "resistor" listed on page 160 (1972 Cutlass/442 assembly Manual). I'll keep looking.

 

I just found a thread which said to look behind the power brake booster. Nothing there. Only things on my firewall are the horn relay and voltage regulator. I don't believe non ac cars had a relay at this point. Which brings me to the question of why would there be juice flowing through the dash harness with the key off? I thought the only constantly hot line was for the light on the rear view mirror which works as it should.

 

The horn relay should be on the driver wheelwell housing (by the fender). The blower relay does kind of look like the horn relay

 

Edward, follow up

 

Thanks Pat for that diagram. A picture lays it out perfectly. So here's a thought. I have an aftermarket radio which has a memory and an EFI control module with a memory function. Both of these have a small feed to the horn relay for constant juice to maintain the memories. Would the combination of these two be enough draw on the battery to create a battery voltage drop of about 0.5 volts over the course of a few days? I used to have a switch on the hot feed from the starter to the horn relay but I was afraid of a cabin fire hazard and the memories would get erased after I shut off power. (Without the car ever having A/C there must not be a relay or 30 amp fuse)

 

Try this previous post;
https://classicoldsmobile.com/forums...wiring-103721/

 

there is a hot feed on the fuse box

 

IF mine I would turn off the key turn on the heater then go to the fuse box and one by one pull a fuse till the heater quits. Follow that wire till you find your problem.... Just me ...Tedd