Dead Blower(s)
Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
Dead Blower(s)
I replaced my upper internal oil thermostat o-ring seal with engine in the car - removed the mass air flow meter and air filter assembly only. I pushed some wires aside to get to the thermostat, and since buttoning it up, my engine mounted blower has no power to it, and so the footwell auxiliaries do not work either. I can't see anything disconnected, and I have already replaced the relay for the blowers in the engine compartment. I have checked all other fuses and relays. Is there an electrical system sleuth out there who could give me a clue? I'm afraid I broke a wire in the bundle that goes through the bulkhead.
Rennlist Member
Joined: Oct 2003
Posts: 282
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From: Marietta, GA
That wire bundle is pretty tight against the oil thermostat and it doesn't have much slack. If you just pushed the wire bundle aside without removing the section of bulkhead and the rubber grommett that holds it, there is a possibilty you might have broken a wire.
But, check the connector at the blower fan, it may have gotten knocked off. I think also that the footwell blowers will not work if the main blower is disconnected.
Did you disconnect any other wires, ground connections, etc. Also check the fuses in the engine compartment (behind the plastic cover on the left side).
The following article does a good job of describing the electrical puzzle that is this system. It might help trouble-shooting.
http://www.porschenet.com/bruns02.html
Good Luck
Andrew
But, check the connector at the blower fan, it may have gotten knocked off. I think also that the footwell blowers will not work if the main blower is disconnected.
Did you disconnect any other wires, ground connections, etc. Also check the fuses in the engine compartment (behind the plastic cover on the left side).
The following article does a good job of describing the electrical puzzle that is this system. It might help trouble-shooting.
http://www.porschenet.com/bruns02.html
Good Luck
Andrew
Last edited by AJ88CAB; Jun 20, 2005 at 05:21 PM.
Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
The connector at the blower fan is secure - I put a voltmeter in the contacts and there appears to be nothing, with ignition on and heater control levers all the way up. I didn't disconnect anything else. I fear that I may have broken a wire. I guess it may mean an expensive trip to the Porsche dealer. You are correct, the footwell blowers are disabled also. The article is great, thanks. What a shame, I was pretty proud of myself for replacing that thermostat o-ring without pulling the engine. Yikes.
Rennlist Member
Joined: Oct 2003
Posts: 282
Likes: 14
From: Marietta, GA
Don't forget to check those engine compartment fuses. I knocked one loose once removing the plastic cover.
I did the thermostat O-ring a rew months back w/o an engine drop also, but I had to take the intake manifolds off and the piece of the bulkhead sheet metal where the wire bundle passes through so I could move the wires. If they had only located that wire bundle 2 inches in either direction that repair would be sooo easy. By the time I had everything off I just went ahead and changed the oil cooler and breather seals, and the pressure switch. Classic "while your in there........"
Let's hope it's those fuses.
Good luck
Andrew
I did the thermostat O-ring a rew months back w/o an engine drop also, but I had to take the intake manifolds off and the piece of the bulkhead sheet metal where the wire bundle passes through so I could move the wires. If they had only located that wire bundle 2 inches in either direction that repair would be sooo easy. By the time I had everything off I just went ahead and changed the oil cooler and breather seals, and the pressure switch. Classic "while your in there........"
Let's hope it's those fuses.
Good luck
Andrew
Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
Andrew,
Thanks, but I checked those fuses also - I ended up checking every fuse and the "booster fan" relay repeatedly. Do you know how to access where that bundle goes after it goes through the bulkhead/firewall?
Dennis
Thanks, but I checked those fuses also - I ended up checking every fuse and the "booster fan" relay repeatedly. Do you know how to access where that bundle goes after it goes through the bulkhead/firewall?
Dennis
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Joined: Oct 2003
Posts: 282
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From: Marietta, GA
I have never traced it but I am guessing that it must go into the center tunnel betwen the seats. Could you have pulled on it enough to have pulled the connector off of the contacts at the heater levers? You should be able to check continuity from the heater levers to the relay in engine compartment and see if it is the wire. Do you have the Bentley manual, there is a good electrical diagram in it that might help. Looks like pin 9 goes to yel/red and pin 11 goes to yellow at the levers.
Good luck
Andrew
Good luck
Andrew
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From: San Antonio TX
Take the 3 fuse phrenolic block located under the cover on the left side of the engine off. There are two small screws holding it to the frame just outside of the large relay. The reason for removing; on the back side of the 3 fuse block, there are copper bands connecting the power from one post to another. I had your exact same problem and found one of the strips for the heater blower had burned through, therefore no power. One way to check it is to get a small length of wire and shunt across from the middle post to the post with the blower fuse. That's how I found the problem. It was burned trough and no power getting through and to the fuse. Hope this helps. I spent almost a day finding it.
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Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
I should be able to look at that tonight and will let you know in the next couple days if that was it. Thanks for the tip! But, what could have caused it? I would think it not normal for that to burn through.
Rennlist Member
Joined: Jan 2002
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From: San Antonio TX
I had the same question, but no answer. Before you pull the block off, take a wire approximately 6"-10" long and touch the middle post and the post for the blower fuse. I have a wire with alligator clips which makes it easier. Make sure the blower motor and switch is on. If it comes on that is your problem. If that is the problem, to fix it you have two options: 1) buy a new block from the dealer or other source, or 2) take the block off and on the back of the block, solder a piece of wire from the middle post to the bottom post (a shunt) to replace the burned through flat copper material. Use a 10 or 12 guage wire (something substantial).
Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
Too late; I pulled the block off (that was a challenge, to get the nuts off and on the back again) and the copper piece is whole and continuous. I was so hoping it was the problem, and of course had that familiar DIY feeling (I have worked for some time, taken something apart and put it back together, now it should work!) to no avail. Looks like I'll be spending some money after all. Thanks anyway.
Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
Whoops, missed the previous posts - I'll try checking which multi pin plug nearby, Dave? And, continuity. I have the Bentley Manual but hadn't taken it that far. Thanks, guys, I'll be able to look at it again this weekend.
Thread Starter
Racer
Joined: Jul 2004
Posts: 479
Likes: 5
From: Fairbanks, Alaska
Andy,
Regarding your post suggesting checking continuity, I did, and it all checked out. I furthermore checked the blower motor two-connector wire clip-on harness again and determined that there was power to it, and good ground, when the ignition switch is on and the heater levers up. Not sure how I missed that previously, I think I neglected to remember that the ignition switch needed to be fully on. And so it appears that my blower motor died, and it was just coincidentally around the time of the top seal change. Seems I didn't break a wire after all, thank God. I have yet to explore replacement blower motors, I understand they are expensive, but at least not as bad as pulling the engine to trouble shoot a bad wiring harness. How many times have two things happened mechanically at the same time and I assumed there was a causal relationship...but that's what makes cars so interesting... Thanks again.
Regarding your post suggesting checking continuity, I did, and it all checked out. I furthermore checked the blower motor two-connector wire clip-on harness again and determined that there was power to it, and good ground, when the ignition switch is on and the heater levers up. Not sure how I missed that previously, I think I neglected to remember that the ignition switch needed to be fully on. And so it appears that my blower motor died, and it was just coincidentally around the time of the top seal change. Seems I didn't break a wire after all, thank God. I have yet to explore replacement blower motors, I understand they are expensive, but at least not as bad as pulling the engine to trouble shoot a bad wiring harness. How many times have two things happened mechanically at the same time and I assumed there was a causal relationship...but that's what makes cars so interesting... Thanks again.
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Joined: Oct 2003
Posts: 282
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From: Marietta, GA
Glad to hear it's not your wires. I had to replace my blower moter and found this alternate solution to work well.
http://forums.pelicanparts.com/showt...ghlight=blower
I ended up using the original motor mounting plate and ground down a couple of spots on the plate and also had to redrill the mounting holes.
Good luck
Andrew
http://forums.pelicanparts.com/showt...ghlight=blower
I ended up using the original motor mounting plate and ground down a couple of spots on the plate and also had to redrill the mounting holes.
Good luck
Andrew