dead radiator fan...

madmax25 · Posted: Fri Nov 16, 2007 11:51 pm Post subject: dead radiator fan...

fun, fun, fun.
1st speed doesn't come on, needle climbs, then the high speed conveniently comes on in the Jack in the Box drive thru and scares the piss out of the poor soul in front of me.

I did the test where you apply 12v to the poles that plug into the temp sensor on the radiator and only got the high speed. traced it to the resistor behind the headlight. Replaced the resistor with a used one that checked out, plugged it in, but no dice.

So if it doesn't work downstream of the radiator temp switch and it's not the resistor, what could it be? How often do the actual fans crap out?
_________________
-Elliot

'88 Vanagon GL "Big Red"
'90 Westy

tencentlife · Posted: Sat Nov 17, 2007 10:10 am Post subject:

Got AC?
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madmax25 · Posted: Sat Nov 17, 2007 12:00 pm Post subject:

yes.
_________________
-Elliot

'88 Vanagon GL "Big Red"
'90 Westy

tencentlife · Posted: Sat Nov 17, 2007 12:15 pm Post subject:

The fan system in AC-equipped vans is quite different from non-AC. The fan motor is single-speed, with the lower speeds a result of dropping the delivered voltage via the series resistor, so if the motor runs at all, at any speed, it and its grounding path are OK.

So, you pulled the plug from the radiator dual-temp switch. Did you then determine which of the three wires is hot with a testlight or VOM? and then jumped that wire to each of the other wires? and only one of them resulted in the fan running, at high speed? If yes to all those questions, you should check out your replacement series resistor again, it may also be faulty. Either that or there is a fault in the wiring leading to/from the resistor pack. As I recall, there is no relay or other items in the current path for the low-speed operation, but I don't have my book nearby so that's all I can offer at this time.
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Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

madmax25 · Posted: Sat Nov 17, 2007 12:29 pm Post subject:

Thanks. I guess I'll do some more digging this weekend...
The old resistor had a dead leg on it that failed a continuity test, the "new" one doesn't. Figured that meant it was good.
I believe the wiring to the resistor is good as well- I tried the 12v test with the main battery unplugged and when I jumped 2 of the legs the fan made a click noise. The other two legs made a click noise in the resistor. With the batt. hooked up I got the high speed fan with one and nothing (no clicks) with the other...if that makes sense...
_________________
-Elliot

'88 Vanagon GL "Big Red"
'90 Westy

tencentlife · Posted: Sun Nov 18, 2007 4:30 pm Post subject:

I'm not getting what you're describing, but the diagram that covers the late AC system, including the fan, is in Bentley on p. 97.143 -97.145.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

madmax25 · Posted: Sun Nov 18, 2007 11:09 pm Post subject:

I don't understand myself sometimes...
Yeah, I'll check the bentley.
Thanks again.
_________________
-Elliot

'88 Vanagon GL "Big Red"
'90 Westy


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