1998 Dodge Caravan Flashing lights

HANDYMAN6638

MEMBER
1998 DODGE CARAVAN
6 CYL
2WD
AUTOMATIC
80,000 MILES

We have a 1998 Dodge Caravan Sport with a 3.3L 6-cyl engine and about 80,000 miles on it. This very well maintained vehicle recently started exhibiting an intermittent problem; i.E.- While the vehicle was parked and engine off, the headlights and parking lights would start flashing for a short time (sometimes as long as 5 minutes) and then go off. This happened several times a day, and apparently when no one was watching, as over a two week period the battery went dead. It was jumped, brought directly to the Dodge dealer in Florida where they said it had a bad headlights switch (with corroded terminals). We were told that it was either the headlight switch or the BCM as the cause, but we did not wish to spend $1000 for that on a "maybe". They then "watched" it for a week, supposedly connected to diagnostic equipment for that time with no subsequent failures. The vehicle was driven home and parked, and the next day exhibited the same symptoms (flashing lights with engine off) 5 times in a 24 hour period.
I have checked many online blogs for similar problems (including here) but nothing exactly matches. So, my sister and I started trouble shooting ourselves (we hope logically) and found two relays (in the box next to the battery) labeled "Low Beam relay" and "Park Lamp relay". We checked the grounding system as best we could (from the negative post to the fenderwell, and then to the fuse block and it appeared to be intact, clean, tight, and not corroded. (Using a good multimeter).
Since we suspect these two relays as possibly being bad (even intermittently) we swapped them out with two identical relays from the "High Beam" and "Cigarette Lighter/Accessory" positions. We are awaiting a longer term period to see if the problems reoccur (they have not in 24 hours) but while we wait wanted to get your opinion as to whether the combination of the replacement of the headlight switch on the dashboard and the swapping out of those two relays could be the solution. (If the problem does not reoccur in say two weeks we plan on just buying two new relays at AutoZone.)

I also saw entries in some blogs about an "IOD" relay that might drain the battery, but nothing about "flashing lights" accompanying it. Any thoughts there?

Sincerely yours,

Randy

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

Unfortunately, this is what happens when the engineers have the insane need to hang a troublesome computer onto every imaginable system. Chrysler, in the past, has had WAY fewer Engine Computer problems than most other manufacturers, but the same can not be said about their Body Computers. Starting with the redesigned '96 models, the most common problem they cause is dead wipers, but there are a whole bunch of other systems controlled by that computer now, including the lights.

I would suggest finding a used Body Computer from a salvage yard and installing it as a test. There is no way to test it other than to install it. Even that is tricky. It is bolted in on the back side of the firewall, in front of the brake pedal. Pulling it down unplugs it from the inaccessible electrical connector. That's why nothing can be easily tested in the vehicle.

The IOD fuse you mentioned is not related to this problem. It is removed to prevent battery drain when the vehicle will sit in storage for more than three weeks. This is done to prevent the many computers' memory circuits from draining the battery. It is mainly used between the time the vehicle is manufactured and is sold and delivered to the dealer. Removing this fuse might stop the lights from flashing on, but it won't address the actual cause of the problem.

Caradiodoc