Heater blower problem- I'm stumped

Steve 82SC · 10-12-2005, 09:05 AM

Car is an 82SC with manual heating levers. The engine compartment heater blower will not activate. Here's what I've done so far:

1. Cleaned the contacts on the floor under the levers. I can hear the relay activating in the engine room.

2. Put new spare relays in anyway...no difference...relay still opens and closes.

3. Fuses are fine....continuaty at fuse block for fan fuse and fan fuse relay.

4. Wired the blower motor directly directly to one of my motorcyle batteries...the blower activated.

5. Here's the weird part...checked the plug harness coming from the car that plugs directly into the heater motor. When I pull up on the floor levers, the test light comes on. Even checked the harness with a meter and I'm getting almost 12.5 volts.

Any suggestions would be greatly appreciated as it's going to be cold in Chicago soon and I enjoy using the car until they salt the roads.

Thanks,
Steve

Ned nyna 11 · 10-12-2005, 09:22 AM

So the motor runs when you wire it directly and you are also getting voltage at the connector. However when you energise the motor with the connector, nothing happens.

Looks like a bad connection between the connector plug and the motor.

john walker's workshop · 10-12-2005, 09:28 AM

try grounding the brown wire in the heater motor plug. you already have power to the motor, maybe the ground isn't happening.

steve911 · steve911's Garage

Steve--
Wasn't clear if you'd tried this (in this order):
Pull up both red levers, then slide the dash control to activate the blowers. I found that the blowers don't work unless the heats been turned on. German fail-safe engineering.

Steve 82SC · 10-12-2005, 01:07 PM

Steve911's post got me wondering........Does the dashboard fan control lever have to be moved over slightly to the right in order for the rear compartment heater blower motor to activate via the floor levers? I know at highway speeds there would be more than enough warm air to warm the car without the assistance of the blower motor and this would allow you to use the floor levers to limit or enhance the amount of warm air entering the passenger compartment. I hope I'm on the right track here. I'm at work now so I'll check this function when I get home this evening. If it works, nothing was broken. I appreciate your input.

Thanks again,
Steve

steve911 · steve911's Garage

Steve, I'm pretty sure that the heater levers have to be pulled upward (on) in order for the dashboard fan control slider to activate the blowers. When the red heater levers are down (off), moving the dash slider to any fan position has no effect (i.e. the blowers don't come on).

dfink · 10-12-2005, 02:36 PM

Don't know about 82 but in my 85 it doesn't matter where you have the front dash levers. The rear fan still should come on when the center levers are lifted grounding the circuit. The front levers only control the front blower. The front floor blowers are another matter. Check all the connections. You could in theory show voltage but have such high resistance that the fan would still not run.

john walker's workshop · 10-12-2005, 03:23 PM

the dash levers have nothing to do with it. you get power all the way to the yellow wire in the plug, and the fan works when you jump it independently, so the only thing left is a ground issue, or the fan just happened to work that one time when you jumped it direct to a battery. they do get pretty loose and worn out. the wires in the plug get pretty crusty too.