Date:         Mon, 18 Nov 1996 09:43:26 -0800
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Ian Webb <ian_webb@virginia.edu>
Subject:      Temp light on for no apparent reason (90 vanagon)

I've got a perplexing problem and I'm hoping to get some input from the
list to try to solve it.  On my 90 Camper, my temperature light comes on
for no apparent reason.  here's the story:  2 weeks ago I switched out
my coolant temp sensor (the blue one) on the thermostat housing to cure
a stalling problem I was having when the van was cold.  I bled the
radiator, but probably didn't do a good job of it.  No problems.  then,
10 days later, its about 27 degrees outside, and I leave for work.  I
let the van warm up for about 5 minutes, get in and start off for work. 
The van is in no way warm--temp guage hasn't moved even a little,
transmission shifts with some effort (you know how it is)--and then the
temp light starts blinking.  I pull over, check the levels of coolant
and they seem ok.  Start back up and go a few miles, temp guage just
starting to rise, and the light starts blinking again.  I stop for a
train.  start back up and a few minutes later, it starts blinking
again.  I get to work and its still blinking, but by now the van is up
to normal operating temperature, according to the guage, the light
continues to blink...

So I bleed the radiator and am able to bleed off a little air.  I think
that was the cause, but later on that afternoon, it starts blinking
again.  So I change out the coolant LEVEL sensor in the resevoir.  The
light stays off for a trip to the mall (about 10 miles) so I think thats
it...then it comes back on.  Try to bleed it again...no air...still
blinks.  And interestingly enough, it doesn't always begin blinking at
the same time.  Just for kicks on Saturday morning, I sat in the van
while it warmed up, staring at the temp light and listening to "Car
Talk" in public radio.  Nothing.  So I start off to Kroger, get a mile
down the road--you guessed it--blinking again!!!

All this while its been pretty cold out, 20's at night, high 30's durnig
day, so I think maybe its somehow related to the outside temperature. 
Yesterday it got into the 50's in the afternoon, so I start it up then
and let it warm up to normal operating temp...no light...get in to drive
around block and it starts blinking again.  I try to bleed it again and
get no air.  

At no time has the temp. guage gone above normal operating temp.  Any
ideas?

just to recap:
	*I have changed blue coolant temp sensor in thermostat housing
	*I have changed coolant level sensor in expansion tank
	*I have checked levels of coolant.  they appear ok.
	*I have heat, front and back (which would suggest that the thermostat
is OK)
	*I have bled radiator several times (which would also suggest
thermostat is OK)

As Joel has suggested, I can try to change out the other (grey) temp
sensor on the thermostat housing, but as far as we know, that works the
temp guage, not the light.  I've been trying to decipher the wiring
diagram in my bentley, to determine EXACTLY what that light is supposed
to tell me, but I not an electrical engineer and am getting no real
useful info from the book...

thanks,
Ian
	
-- 


Ian Webb, Assistant Director
University of Virginia Roanoke Center 
Phone: (540) 857-7922
Fax: (540) 857-7936
ian_webb@virginia.edu