When my Corvette (coup) gets wet (rain, wash) the interior dome light
comes on and will not shut off until the affected area drys out.
Sometimes this takes hours. It has been suggested that the dash light
switch is somehow getting wet (under the dash) but I cannot find water
inside of the car on that side, except under pressure (wind/hose) water
will leak through roof panels on both sides, but does not run toward
the dash on either side. I believe the only other items on that
particular circuit would be the lower courtesy lights on both sides and
the door switches and have replaced the switch on the passenger side
without luck. I'm thinking a short would blow a fuse but to date that
has not happened. The dome light has been disassembled but shows no
sign of ever being wet. Any ideas as to how I might go about
solving/tracing this problem? Referrals to other Corvette related
websites might also be helpful.
You are correct. The problem lies exclusively with
the dome light. As you probably know, by design it
has a delay feature built in to it that under normal
circumstances keeps the light on for about twenty
seconds after exiting the vehicle. But when
"something" gets wet it will not shut off. As I write
this the car is with a reputable mechanic who is just
as perplexed as I am.
I took a quick look at the wiring diagram. The left door switch has
three terminals and the right, two terminals. IIRC, my '79 Pontiac alsi
had two switches and I had a problem with the driver's side
switch--never traced out the extra wire though.
I've got to make a quick run out to a site in the desert. When I get
back I'll trace out those wires and see if a leak down into the left
door pillar might be the culprit. Ditto the harness connectors.
Diode, bless his cussed being, was an expert on those delay modules.
Wish he were here now.
Easy answer: After a "dumb stare" at the schematic I'd meander to the
rear of the car and check out the wiring and socket for the spare tire
lamp. Looks like you might be picking up a ground on the white wire
back there. Possible "damp" area (:-)
Just for info, the three wires from the Left door switch provide grounds
White -- ground for the dome light circuit and the courtesy delay module
Tan -- ground that goes via a contact in the steering column to the
seat-belt & ignition key warning buzzer (sounds when the door is open
and the key is in the ignition)
LtBlue -- ground to anti-theft system
Right door switch is same without the (tan) key signal.
Hard answer: If this doesn't do it and key alarm and anti-theft are
working OK then I'd look at an an eight-cavity harness connector (p/n
8900441) under the dash. The White wires are the ones that carry the
grounds to the lamps. Other colors on that connector are Yellow, Dark
Green, Pink, Light Green, Orange and Light Blue. The small-harness side
of that connector heads for the rear body and has the two white wires
that go to the dome light and the spare tire light. (All of this
assumes that my schematic is the same as the harness in the car.)
Extra hard answer: The problem is in the delay module or in wiring on
the 'large-harness' (dash) side of the above connector -- one of those
jobs no one wants -- unless we can find Diode to supervise and there's
Let us know if you found something.
Thanks for the info. I will pass this along to my
mechanic and will advise you of success/failure. I'm
probably going to have to purchase wiring diagrams for
them as they have indicated what they have appears to
be inadequate. Any advice as to who produces the best
after market product?
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