90 caravan a/c electrical problem, can I ask here?

cghost · Lieutenant Joined: Apr 02, 2004 Posts: 266 Location: USA

I have a 1990 caravan with 190k miles that I'm having some electrical problems with-is that a kind of question I can describe and get help with here?
Thanks

Mariner · Posted: Fri May 28, 2004 10:30 am Post subject:

Can but try. If we know he problem, someone may well have the answer. Rack it up, then!! Very Happy

cghost · Lieutenant Joined: Apr 02, 2004 Posts: 266 Location: USA

90 Caravan, 190K miles, been starting and running great through fall, winter, spring. AC has been retrofitted to 134A, not in good shape overall.

Tues had it checked, bubbles and pressure readings lead mechanic to following proposal-which I did. Evaporator (expansion) valve (rectangular brass box on firewall) bad. Replace, recharge, etc.
AC fan (the one behind the aluminum finned air conditioner radiator thingy) is not working properly, grounding the relay will make it run all the time.

Car worked fine leaving the shop. 3 hours later it wouldnt start, just clicked. Mechanic said battery down. Got it back to shop late Tues night.

Wednesday.
Mechanic, battery ok, alternator ok, no draw on battery. I cleaned the connections. He started car for my wife about 5pm and showed her how he'd grounded the relay. At 10 that night when I got car, it barely started, but restarted fine after drive home.

Thursday AM, dead in driveway.

"Grounding the relay"
There is a bank of silver boxes on the driver's side fenderwell. On the front one there are two connectors, one with multiple wires and one with a single brown wire. He cut the brown wire, left the one end hanging out of the harness and connected the end of the piece of wire still connected to the relay to the fender well. This coused the ac fan motor to run all the time the switch is in the forward postion.

Conundrum how to proceed - to at least get car back to running-proper fix on ac is a longer term issue.

I dont know whether to suspect the battery that checked good is really bad, or there is a draw that didnt show in his tests or there is some other component that got zapped in his tests.

cghost · Lieutenant Joined: Apr 02, 2004 Posts: 266 Location: USA

I see I was a little unclear with the I's, Mechanic did all repairs, I paid for them.
Cant remember when battery replaced but it's probably over 3 yrs old.

Mariner · Posted: Sat May 29, 2004 6:03 pm Post subject:

Hi,

First off, batteries do lose their ability to hold a charge over time. This dependent on use, maintenance etc.

Basic test. Have battery charged, leave in vehicle and see if it will start motor next day. If battery dead, remove battery and have it checked by an auot-electrician, NOT a mechanic. A simple powerdown/leak test will show if good or not. Even a good parts shop can perform this test for you and, usually at no cost. If bad, replace battery. Takes but minutes, often less.

Assuming battery bad and you have a replacement, put in vehicle. Run as normal, see if will start next day. If yes and no problems, then the battery was your problem. If battery dead and will not start motor, suspect the system.

A distinct possibility is that of an Earth Leak, which will run down a batterey no matter how good it is. A good auto-electrician will find this. A bad one will not. Choose wisely.

Earth leaks are hell to pin down as they could be anything from the starter motor to....well, you name it. If it is earthed, it can leak, it's that simple.

Sorry, but cutting a connection that was placed their by the manufacturer and has served you well is not a solution, it's a workaround by a lazy mechanic who either knows what the problem is but A: can't be bothered to fix, or B: does not know how to fix.

Before doing all this, ensure the connections cut by the mechanic are restored, otherwise you will A: have other problems, or B: have something that no longer functions as it should. Either way, have those connections restored in order that you can simulate the exact same conditions that were in evidence prior to your electrical problem.

When you refer to the AC fan do you mean Air Con or AC as in current? Either way, there is a problem there as the mechanics workaround shows. Either the guy can fix it or he can't. Suspect that as a potential source of drain.

Try the above starting with the battery only after having the cut wires made good.

cghost · Lieutenant Joined: Apr 02, 2004 Posts: 266 Location: USA

Hi Mariner
Thanks for time to answer, have partial fix, will give you better feedback when I've got more time-used my time up on logs today.

cghost · Lieutenant Joined: Apr 02, 2004 Posts: 266 Location: USA

Hi Mariner.

Sorry about not getting back sooner. When I'd have a little time I'd see a log and think maybe I can do that one and my time would go. May be out of that for a bit.

I disconnected the repair. I was then sometimes getting enough juice for 1 start.

I then had some onetime help not usually available to me. I asked our maintenance man at work what to look for in a battery charger. He asked me why, when I told him, he said I didnt need one and had me get the car to our work. He tested the battery-it showed ok with a meter, but when he put a load tester on it, it looked awfully weak.

I replaced the battery, but left the fix undone.
Again another unusual help, I happened to be in a situation where a relative did some more testing for me and told me to put the fix back where the fan was running all the time.

I did that and still experienced no more problem-so it was the battery. Whether it was going bad or was ruined by something in the a/c (air conditioner) testing /repair process, I don't know.

If I keep this vehicle, I will be in a position later this summer to get it fixed properly by a really knowledgeable person-I've forgotten the terms now but there are 3 different parts that send air conditioner fan on/off signals to the car's computer and he can test them for me and figure out which one is bad.

Appreciate your efforts for me.


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