Hi Tom - At 12:01 PM 1/27/2013, Mister Tom wrote: >Both problems come and go. >My question is whether this is the typical symptom for the electrolytic cap >on the instrument cluster going bad. If it varies with humidity then it's completely typical; otherwise maybe/maybe not. During one of the spells while it's misbehaving, check for +10 V +/- 0.5 V between ground pin on the thermostat (the skinny one) and whichever of the other two gives the higher reading. If bad, you have a bad panel regulator or a contact problem on the panel. Then remove the level controller module from the relay panel. If the misbehavior continues (and +10 V is good) then it's definitely inside the gauge. If not it's either the controller itself or more likely an intermittent open in the wiring to the sender. >2) The fuel gauge needle will drop slowly, from an accurate reading, all the >way down to the reserve mark. > >I watched it fall from a little over half to the reserve mark in about ½ >hour while driving. If the temp gauge is dropping at the same time, then it's the panel regulator or its connections. If the temp gauge is steady then you can eliminate the regulator. It sounds like a flaky connection that's gradually increasing resistance when live. Or conceivably a heater short inside the gauge. There is only a heater inside the fuel gauge, no electronics. If you drop the rear of the tank an inch or so you can get your hand far enough in to unplug and replug the sender in case that connector is flaky. Also cycle the B and E connectors on the back of the fuse/relay panel, and the instrument panel connector. >The fuel level is indicated correctly after turning the ignition off and on >again. I can't explain that, if you meant that just cycling the ignition cures it temporarily. There aren't any electronics to reset except the regulator itself - and if it were giving a problem you'd see it on the temp gauge as well. This could make it a real stinker to find. This would be a good time to have a spare panel to swap in (or spare fuel gauge ditto) to eliminate the gauge as a possibility. The wiring goes from panel connector pin 7 to B3 on the back of the fuse/relay panel; then back out through E5 and straight to the sender. With the panel unplugged you should see about 35 ohms to ground with the tank near full, and about 170 when you've just hit the reserve. You could break the panel supply lead (black, pin 8) and insert an ammeter, then let it sit while the gauge goes through its cycle. If the current rises as the gauge falls it's a short in the gauge; if it drops it's a resistive connection in the wiring. Yours, David |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.