globalmike

So here’s what’s happening with my car. The battery is completely discharging and then obviously it will not start. The battery is good as is the charging system.
-with car running the terminals of the battery read about 13V
-positive to ground (engine) about 13V
-with the car off the battery will drain quickly
-with the car off and the battery disconnected the battery will gain voltage as expected

So my question is what is the most common source of voltage drain.
Should I attack this problem by leaving the car off and removing fuses till the voltage stops dropping


Thanks in advance
Mike

globalmike

I think that I found the problem the fan relay (G10) is draining the battery. I unplug the relay and the battery does not drain. Is there any way to check to the relay to make sure it is the culprit.

What should the resistance be between the terminals.
Who sell these things,

Mike

Bri Bro

Before you replace the relay, make sure both of the fans are working correctly. The easy way to test it is to borrow a known good one and see if it works. They are hard to test. Two inputs from the radiator temp sensor (one high, the other low fan speed), one input from the AC controller(high speed fan when AC on) , the low speed resistor paths for the fans, and several power inputs.
http://www.paragon-products.com/prod...615.104.03.htm

bearone

13v running is too low, the batt is nowhere close to being fully charged, should be upper 13's to low 14's.

when you remove the key the fan/s should run but then shutoff. most likely it's a bad thermoswitch in the upper left corner of the radiator.
clarks garage has a good writeup.

87951
95sl320 dd

VOoDOoGTX

to change that switch is a bitch without a lift but with a lift takes about 10 seconds.

Bri Bro

If the switch is bad, the fan runs all the time or doesn't run at all. Do the fans run all the time?

bearone

no lift needed.

i replaced the switch one time-1 1/8 deep socket and then the radiator, fans/shoud on ramps.

87951
95sl320 dd

95ONE

Or.. As my problem was. Wires going back and forth to the resistor pucks have burnt through their protective layer and are grounding out.
Do a continuity test between wires and ground for giggles.

sebastian944

I think i have this same problem too. Sometimes the fans run longer than 30 seconds.. sometimes up to a few minutes. Should i replace the thermo swtich and the fan relay when i change my radiator in the spring?

sebastian944

Why is this relay so bloody expensive?

Bri Bro

The fan relay has several large relays (carry current for the fans) inside of it and some control electronics but I agree, it is overproced by x3.

I have had problems with the shutoff of the fan before. I pulled the relay to shut off the fan after I parked the car. Next day I put it in the socket and it has worked since. I am guessing the contacts were dirty and plugging/unplugging the relay wiped them clean.

globalmike

thanks for the reply’s.

So after more work and I have to agree that the problem is more than likely the rad thermo switch is this the part from paragon. (its also cheaper than the relay, which might have to be the next part if the switch does not fix the problem)
http://www.paragon-products.com/prod...606.118.00.htm

Bri Bro

Not that part, this one.
http://www.paragon-products.com/Shop...606%2E481%2E00

As stated above, if the fan isn't running all the time, this part will not fix the problem, it is a temp switch connected to the fan relay.

bearone

thermoswitch is a vw part.

87951
95sl320 dd

globalmike

thanks everyone. i ordered the part