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Join Date: Oct 2005
Posts: 35
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Voltage, Charging, Cooling Fan Problem
My car: US '88 951 220 hp stock, 178K miles
Instrument panel voltage gauge sometimes reads 13-13.5. Other times it reads on 12v. When it reads 12 v, the cooling fans don't come on unless I turn on the AC switch. Also, the battery isn't charging when it reads 12 v. When it reads 13-13.5, all is fine. When I turn on the AC, the volts drop .5V (whether reading 13-13.5 or 12v), temp gauge jumps up equivalent amount. Car has an aftermarket radio. It has factory alarm with may or may not work. Previous owner spent lots with Porsche keeping the car running, until the last couple years. I'm a recent buyer. The engine seems to run great. Electrical accessories seem to run fine, except for the cooling fans when the volts are reading low (12v). Anyone have experience with this or very similar problem? I'm just starting the troubleshooting. TIA.
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Woody H. A81Sturmer '88 951 White |
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10-28-2005, 01:28 PM
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Posts: 35
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I've had the weekend to think about this - and cruise the 924-944-968 forum & Clark's Garage. I did not find anything definitive but... it must be something that links the fans and the charging system, but does not affect the fans & the AC system - since the fans run anytime I hit the AC switch, whether the volts read 13.5 or 12 v. What could cause the volts to drop and the fans not to come on with the temp switch, but still come on with the ac switch? Anyone have anything more specific than a bad ground? Maybe a specific grounding point? It's an intermittant problem, so it's probably a wire or relay (probably a relay) that "works" sometimes but not others. AND when it doesn't work in also causes the volts to drop (and the battery to not charge). Suggestions?
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Woody H. A81Sturmer '88 951 White |
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10-30-2005, 11:19 AM
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Ornery Bastard
Join Date: Sep 2001
Location: South Sound
Posts: 2,879
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Voltage should _never_, not under any normal circumstances, read below 13 with the engine running.
Something is an intermittant fault in the charging system.
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--------- Silver 1998 Volvo S70 T5 <- Daily (Anja) Guards Red 1986 951 <- Seattle car (Gretchen) White 1976 914 2.0 F.I. <- Prodigal car, traded away then brought back again (Lorelei) |
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10-30-2005, 11:25 AM
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Posts: 35
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Right. I'm trying to narrow down what it could be. The problem also affects the cooling fan temp switch circuit. When the volts drop the cooling fans don't come on as the temp rises. BUT the fans do still come on when I hit the AC switch (GOOD thing.)
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Woody H. A81Sturmer '88 951 White |
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10-30-2005, 12:04 PM
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