At 08:29 PM 7/31/2003, mark drillock wrote:
>blinking. I have seen blinking and needle weirdness caused by the sender
>wire being routed too close to the exhaust pipe near the thermostat
>housing on a 2.1. The insulation had melted through and whenever
>vibration caused the bare wire to touch the pipe the led would flash. If
>it touched solidly for long enough the temp needle would rise too but
>when you pulled over to the side of the road it would drop to normal and
>stop blinking. Drove my friend crazy.

Right -- only takes a very short signal to trigger the blink which then
continues for several seconds regardless.

>van. The blinking problem drove me batty until I noticed that her
>alternator output voltage dropped completely at certain rpms. The led
>blinking seemed to be rpm related too and was worse when the headlights
>were on so I looked at grounds first. Finally I replaced the alternator
>and the blinking episodes ended. Too bad I couldn't look at the dash
>voltage with a scope as I bet it would have shown some drops that fooled
>the led circuit into thinking that the key had been turned of and back
>on.

It's very sensitive to input voltage -- I'm not even sure it will get all
the way down to 9.5 without starting to blink.  9.499 maybe... <g>

The newer ones I've seen have tantalum timing caps instead of aluminum, has
to help -- but I don't think they cleaned the boards enough to handle
humidity gracefully, and of course as the cap gets leakier it takes less
shunt resistance to upset everything.

d

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"