a/c blowing heater fuse
 

I've heard of this problem from someone else in texas before, but never found a solution. My 85.5 944 is doing the same thing, blowing the heater fuse after about 5-10 minutes after using the a/c. The system blows cold before the fuse blows, it's the heater fuse popping, not the a/c fuse. Going up one size does not help, and the frequency of blowing increases as the system is used. Anyone? the local shop was no help.

I know this sounds weird, but check to see if you have a switch on the power steering pump. On the 944 "S", this switch is used to realize if the idle has dropped after the a/c is turned on. If it has dropped, it sends a signal to the F.I. to increse the idle. If the switch is wasted, the heater fuse burns up.

Just my .02

Check the relay.

Clean battery terminals, fuses, relay (inside and out). Mine was doing this. I did not have a good battery ground. Besides the main battery terminals, check the small bolted connections on the cables.

A factory trained wrench also told me there is a capacitor on the AC clutch whose purpose is to lessen the jolt to the electric system when the clutch engages. If the capacitor is leaking, clutch draws too much current that will cause fuse to blow.

is there an easy way to tell if I have this switch on my power steering pump without too much effort? it's tough to see down there... http://www.pelicanparts.com/ultimate...s/mvc-494E.jpg

Same thing was happening to my 85.5 944na. Replaced many fuses (all kept blowing). Took it to the Porsche Dealer, they replaced the relay. Worked great for an hour then blew the fuse again. Finally replaced the A/C clutch...problem solved. No blown fuses for over a year. Hope this helps.

Hey Bob. Your 944 is sharp. Is your driver's side fog lamp aimed too much to the right? Lens of camera picks up the glare.

Damn, you caught that.... one mounting screw has broken off that one... so it is held on by only one screw, and thanks, it's still a great car inside and out

YOU GUYS:

Bob just got his fog light fixed:
http://www.pelicanparts.com/ultimate.../mvc-494Ee.jpg


but as soon as the word got out, his car was stolen:
http://www.pelicanparts.com/ultimate...ads/wwwwww.jpg


what are we gonna do!?!? http://www.pelicanparts.com/ultimate/wink.gif


SHAUN


[This message has been edited by mideastmafia (edited 07-21-2001).]

nah, not stolen.... just covering 500 miles of the blue ridge parkway at over 60 mph average (medium traffic and construction) and 29 mpg (mostly in 4http://www.pelicanparts.com/ultimate...luridgpkwE.jpg
th gear) :^)

What car???
http://www.pelicanparts.com/ultimate...ds/bobs944.jpg