Heater fan does not work AND its WINTER

[1985RedTarga]

Ok, fairly new to Porsches. I'm still getting used to the heating system. It's my understanding that you pull the 2 levers up and it opens the heat exchangers to bring heat forward. It does just that. Now, when I turn the dial thats right there, nothing happens. I've been told that this is a fan switch that will blow all that hot air.

I need to boost the air flow. I checked the fuses in the engine compartment and they look good. Where do I start to check? Anyone with experience on this topic?

This is a 85 Targa, not the auto heat type.

Thanks!!

[Joe Bob]

Put power to the fan direct to test....if it works it's likely the footwell blowers have issues or the switch between the seats.

[DRACO A5OG]

+1 what Joe Bob wrote

or

turn the key to ignition, then pull the red levers up and the engine blower motor should turn on.

If not, the switches at the levers are not making contact. The switches are connect to a copper contact and when the levers are up, the contact is switched or should be.

If the switches are making contact and the motor is running, turn the dial to 2 or 3, the foot blower should kick in, if not the blower motor/s may be shot.

Hope this helps.

If all motors work, then get under the car and ask a helper to raise and lower the levers, the flaps should open and close fully, if not adjust, using a needle nose and 8MM socket, you may need to spray some lube to loosen the nut, they tend to rust lock.

[j911brick]

Doesn't the left flapper box have some kind of senor in it?

[1985RedTarga]

Thanks. Gives me some place to start.

12 volts to the blower fan i guess???

[Joe Bob]

Yup....I would pull it and bench test.

[1985RedTarga]

Ok, pulled the fan from the engine compartment today and hooked it up to DC. Worked fine. The fuse in the engine compartment is still good. Where should I go from here???? Could it be the rotary switch?

And how does one turn on the footwell blowers???? While I love my car, the heating system is confusing as all get out!!

[daniel911T]

Obligatory smart ass answer: Backdate. The engine mounted fan rarely fails.



Back to real troubleshooting.

-Dan

[FrinkFrog]

If the '85's are like the '83's, couldn't the problem maybe have to do with the blower fan in the dash... located on the firewall in the trunk compartment? I had to service mine with lubrication after it began squealing loudly (and according to members of this bb... before its ultimate failure w/out maintenance). Can Jamie check that fan the same way he checked the fan in the rear engine compartment?

[DRACO A5OG]

Okay now check the two levers at the e-Brake. Make sure switches engage when you lift up on the levers. Switches are connected to yellow wires.

[1985RedTarga]

Draco, they do make contact. Now where?? lol

[aj88cab]

If the contacts are good, I'd suggest your next check would be to find a local owner of a similar Carrera thru Pelican or PCA that has a know working heater system and switch out the heater control unit to test. My experience has been that more times than not, it is a bad controller unit. It is located on the relay panel in the engine compartment.

The footwell blowers will not run if the engine blower doesn't run. If you get the engine fan to run with a good controller unit, you may find issues with the footwell blowers. If they haven't run in a while they are prone to problems. You could bench test them in the meantime.

Also, there are two fuses on the engine comparment fuse block associated with the heater system. One for the engine blower fan, the other is power for the controller unit. You only mentioned one fuse above, so make sure both are good.

[djbrand1]

Yup, just went through all this with my 84, although I have the autoheat. That relay in the rear fuse panel is a fickle one. Try swapping that out, after you confirmed the rear blower works by putting 12v to it. I found that my rear blower needed to be rebuilt before proceeding with the troubleshooting.

[djcdmv]

Subscribed... Mine only works intermittently.

[86 911 Targa]

Originally Posted by djcdmv

Subscribed... Mine only works intermittently.

While the heat is on, tap on the heater relay unit in the engine compartment.

If that creates the anomaly, open up the unit, and clean the relay contacts.

Let us know what you find.

Good luck,

Gerry

pm me as needed.

[1985RedTarga]

Ok boys, here's where I stand...as stated eariler, all the fuse in engine compartment are good. The blower back there was bench tested and fine. I cleaned the relay back there too. Even tried tapping it with a screwdriver. I also was able to bench test both the footwell blowers, they're good.

Now Mr. Bently said there are fuse for each blower in the footwells. I surely didn't see any there. Can anyone advise me on that one?

So where to now experts? I'll have my multi purpose electrical tester back this weekend.

[shadowjack1]

I had the same problem. Turned out to be a bad ground between the blower and the engine.
The blower motor grounds to the back of the alt.

[86 911 Targa]

Originally Posted by 1985RedTarga

Ok boys, here's where I stand...as stated eariler, all the fuse in engine compartment are good. The blower back there was bench tested and fine. I cleaned the relay back there too. Even tried tapping it with a screwdriver. I also was able to bench test both the footwell blowers, they're good.

Now Mr. Bently said there are fuse for each blower in the footwells. I surely didn't see any there. Can anyone advise me on that one?

So where to now experts? I'll have my multi purpose electrical tester back this weekend.

Jamie,

My Bentley does not show the footwell blower fuses until the 1988 M/Y.

Porsche added the fuses along with others in the late '86 production run.

Please check my post "Added fuses and relays".

pm me as needed.

Good luck,

Gerry

[1985RedTarga]

That would be why I couldn't find them Gerry. lol I guess I read the wrong year. I'm going to try the ground suggestion from above. My motor was pulled right after I bought her and rebuilt. Maybe they didn't hook it back up. But I thought Mr. Bently said the ground was right next to the coil. Maybe that's for the rear fuses. I'll give a look.

[Autoban]

On my '86 Carrera the blower motor in the engine compartment comes on when I pull up the levers between the seats. The footwell blowers only come on if the two levers are up and I turn the dial switch by the two levers.
You bench tested the blower motor in the engine compartment and you checked the switches (red levers) between the seats. So your problem is between these two points. Did you measure with a meter that after you pull the levers up there is 12V arriving at the blower motor? Did you measure that there is 12V at the two levers between the seats and after you pull the two levers up the current is going through?
Since all action starts with pulling the levers up you need to follow the current flow step by step to the blower motor.

Juergen
'86 Carrera Convertible