Date:         Sat, 5 Jun 2010 11:59:48 -0700
Reply-To:     ron johnson <rcj.yes@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         ron johnson <rcj.yes@GMAIL.COM>
Subject:      Re: A/C 3rd Stage Relay?  was lower front grill....  RESOLUTION
In-Reply-To:  <2497343F-D1A3-4D26-AE75-7A387891350A@gmail.com>
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Reviewed Bentley again and comments and Alistair's blog entry on his friend's recent fan issue and decided that it really had to be the 3rd Stage Relay.

Since the fan ran when both the Thermo-Switch and the Cooling Fan relay were unplugged and the van is a '91 with A/C, the only other power source was through the 3rd Stage Cooling Fan Relay [Bentley 97.145]. Normally, the 102'C side of the Thermo-Switch needs to be on and the A/C controls need to be on for this relay to be on. A/C controls were not on and the Thermo-Switch was not on which led to the conclusion that the relay had somehow stuck on by itself.

Yesterday, I was unsuccessful at removing the left side vent to access the relay and fuse.... but had done a lot of wiggling of stuff in the attempt. This morning the fan was off! Oh no! Troubleshooting nightmare - I had turned a solid fail into an intermittent problem.... uggh!

To try to get a look at the relay/fuse, I dropped the fuse block down and could then see the relay sitting behind the vent hose..... a little wiggling and it was loose!
So why was the relay stuck on? And why wasn't the fan on today? A small amount of corrosion had formed between the 12V power terminal of the relay and the power contact for its solenoid. The corrosion was forcing the relay on and yesterday's wiggling had disturbed the corrosion enough to break the current path. Interesting. (And I hope this is the answer!)

Thank you to all who offered help/advice/suggestions.

P.S. Tip - attaching a small magnet to the shank of the screwdriver will help hold screws in place while reinstalling in awkward places where you really, really do not want a screw to get lost. And I needed to move the van to be better protected while working on the driver's side - surprised to learn it would start and drive okay with the instrument panel mostly disconnected - odd, but okay for a short run.

Ron J.
PDX, OR
'91  Betsy