Caravan Electrical Ghost?

Never ceases to amaze me how one car in this house gets fixed, another
goes down...

My mother's Caravan (I think it's a '96 or '97, at most a '98) has a
new problem: seemingly at random while the car is on, every analog
guage goes dead, every digital display on the dash wipes out and
virtually every warning light comes on (oil, seatbelt, check engine,
ABS, etc.). There's no change in the performance of the car though -
no limp home mode, no rough running, you have have no spedo, tac, gas
guage, etc.

It has been to the dealer twice. The first time they said there were
all sorts of error codes on all 6 computers, and that tracking it down
would be quite the task (aka expensive). They reset the codes,
test-drove the car, and no problems. Got it back and no less than 24
hours later the same exact problem occurs. They've had it for 48 hours
and said they'd reset the codes again and try test-driving it
themselves - during a phone conversation with them earlier today, it
was pretty clear they had not taken the vehicle out though. Still no
sign of the ghost.

Needless to say this is something I'd prefer to track down myself
rather than have them do it, but I'm a little stumped as to the source
of the failure - it seems to me if there's a problem with one of the
computers, the techs should have been able to spot that right away, or
at the very least the performance of the car would have been affected.
Same goes for a short or something I'd imagine.

Wondering if this could also be a problem from previous repairs; the
ABS on the van has been serviced several times in the last year or so
for problems, and the other month the gas tank sensor went bad and had
to be replaced.

Anyone got some advice on where to begin looking?

-- D

 

There are several ground connections on the van that I would check first
given that multiple systems appear to be affected simultaneously. I
believe the service manual points these out in one schematic.


Matt

 

if you don't have a high quilty scantool you will be chasing your tail

 

My first thought is the ignition switch. If everything that requires the
ignition switch to be on goes off then perhaps that's the problem. My
neighbor had to replace his Honda Civic's ignition switch and was told it
was because of a key chain with loads and loads of keys putting stress on
it.

 

I have a 1996 Town & Country. Last year, the radio could suddenly shut
itself off for no reason. Then the ABS warning light would go off suddenly
and rendomly. I sent it back to the dealer. They could not find any thing
but reset the codes. The problem did not go away, but more bad things
happen, the battery seemed disappered for a fraction of a second while the
car was running. However, that gave me a hint that the problem might come
from the battery.
Finally, I decided to check the battery myself. That was it. The battery
terminals were very dirty. I cleaned them up and hooked them back TIGHT.
The problem was gone since.
Hope this may help.
Gary

 

Over the last few days, people wrote in ten foot tall digital flames:

[snip responses]

1) Gonna try to check the ground connections this weekend. I haven't
had the car to check the manual or the connections yet, but that's the
first place I want to look.

2) I wish I had a scantool Anything that can't be fixed with basic
equipment is gonna have to be a shop deal.

3) Shouldn't be a problem with heavy keys killing the ignition switch
through the weight, but I'll put that doesn as something to check.

4) Checked the battery terminals for crud and they're fine. It's also
not likely the battery as it was replaced last year.

However, the progression of symptoms sounds similar - first the radio
began to have issues, and now the whole dash is basically cutting out.

Regarding re-occurance of the problem, it's been out two days,
including a trip to NY and so far no problems. We're pretty much at
this point just trying to figure out if this problem is happening in
response to a certain stimuli - ie, hitting a bump in the road,
primarily highway or city driving, gas tank at certain level, etc.

Another thing - it's not the factory radio in there - my father
installed a new audio package in the car. Personally I think it's
something my father has screwed up or a wire wore or something, but I
haven't told him that yet. (His handiwork isn't quite 100% perfect).
Is it possible for a short or dropped wire there to affect the dash in
such a manner (vs just blowing a fuse or shorting just the radio)?

 

my dad's 90 Imperial has a digital panel, and it goes blank occasionally,
and then comes back on. it's just the panel, the info center at the roof,
and the radio and everything work fine. probably a wire short somewhere.

it shows every light, because it thinks it just got turned on.

took it to the dealership about a year ago, they couldn't find anything
wrong. the outages used to run to 10 minutes or longer, now they usually
stay under 10 seconds.

not gonna spend a lot of time or money figuring out what's wrong with it,
since the passenger doors got crushed by some stupid woman in a new Cadilac.
thought the stop sign only applies to cars costing under 25 grand, I guess?
we'll get rid of the car in a few months. right now, it's used for a twice
a week 120 mile commute. racking up around 11k miles every 6 months.

 

You need to look at the instrument cluster power , cluster grounds and
the data bus feeding the cluster for your problem. It might fix
itself if you reseat the cluster connectors.

 

The connections have all been taken care of; problem is still there.
Interestingly enough, the car also started having problems starting in
the last few days; the shop diagnosed a bad starter, but it seems a
little too unusual that this problem's popped up just a week or two
after the instrument cluster began acting up. Anyone got any ideas on
that?

Original problem: Analog and digital guages cut out apparently at
random; seatbelt, airbag, ABS, engine light all come on. At first it
looked like this was happening every 6 days, but it missed the last
cycle. Car continued to run normally until yesterday - no rough idle,
no hestitation/stalling.

New development: Car did not want to start, also apparently random
(wouldn't work first few times, would then work fine, run, stop, start
fine again, run, stop, not work). Shop claims bad starter (replaced @
$200 cost).

- D

 

The connections have all been taken care of; problem is still there.

Bad ignition switch???

 

Bad ignition switch???

Well, when the dash dies, my mother has tried jiggling the keys
(assuming the ignition switch has a loose connection or something) but
that has no effect, so unless the ignition switch went bad in another
way. The real problem is the shop is basically telling us they can't
track down the problem; all 6 computers are throwing all sorts of
codes, and worse, this problem can't be replicated. There doesn't seem
to be anything that specifically causes the dash to die - it just
randomly happens, usually when the car is being driven, but it's all
random during that.

If it is a bad switch, is there an easy way to check it?