1990 Caravan wiring

I have a 1990 Dodge Caravan that has a strange problem....The dome lights all
work, but the ones in the rear lift gate. I have probed witha VOM and found
that I have 10.33v when the door is open and no light bulb is in the socket. If
I place the bulb in the socket, I get 0.00v

The question is what is the problem??

I have checked the bulbs in other dome light fixtures and they work, but
anytime I place a bulb in the rear sockets the voltage drops to 0, if I take
them out then I get 10+

I am assuming the bulbs are fine as they work in other sockets, and that the
fuse is also fine as if it was burned I would have no power at all anytime.
What else could it be.

BTW To get the 10+v I have to have both bulbs out of thei sockets. If either of
them is installed then it drops to 0 on both sockets. This seems like a short
somewhere to me, but why only when the bulb is inserted? Why don't the other
dome lights have strange problems? Are the rear lights controlled by any
switches in the rear door? or just the same switch in the front door?

It is a confusing baffling problem!!

Thanks
Jeff

 

(Keyed4U) wrote

Not a short. You have a broken wire.
Test the voltage from the socket to the battery ground(car frame).
If you get 12v then the ground lead is broken.
If you get 0v the dome light power feed to the hatch is broken.
Leave the bulbs in for this test.

IIRC on this car this circuit uses ground side switching.
If this is the case here,
you will get 12v to frame with dome lights on or off.

Look for corroded connectors, possible.
In hatch.
Body side wiring usualy runs under interior moulding and
down rear piller, so you can check there too.

Or break internal to the cable harness between the hatch and body.
Very likely.

If wireing goes under headliner(unlikely).
Note that headliners break **very** easily.

 

Ok.... I have searched everywhere for a plunger type switch to no avail. Is it
possible that it uses a mercury switch? I am assuming that the under the hood
light is one and thought that possibly the rear might also have one. If not can
I simply drill a hole, install a plunger type and ct one of the two wires to
the lights? I haven't torn the rear inside cover off yet either to see if there
is someting going on behind it.

 

The Ground wire on the rear latch is corroded off, remove the laiftgate
panel and you will see the little white grommet with 2 copper tabs on it, im
sure they are broken, this normally happens when the vehicle is equiped
with a rear wiper.....the fluid is highly corrosive and over the yrs they go
bad.....if you havent had the liftgate recall latch replced have that done
and it should fix your problem
Glenn Beasley
Chrysler Tech

 

How can I find out if it had the recall done as well as have it done and not
cost me anything?

I bought the van used a couple of weeks ago as a project. It has been a tinker
toy, but nothing major so far!!

 

Have local dealer look up VIN.

Recalls are usually non-expiring, but I may be wrong.