Author Topic: heater fan quit (Read 5055 times)

passatdiesel · « **on:** December 09, 2008, 01:04:42 pm »

Up until a week ago, I only had high speed on my heater fan. My resistor pack probably blew the thermal fuse. Then as this week went on, the fan quit come on intermitantly and finally quit.
So what I've done is fix the contact on the fan speed control as to make better contact. With my voltmeter I've got power coming from my fuse panel through the 30 amp fuse down the black/red strip wire to the control unit. I have voltage across all 4 contact points on my resistor pack, but the blower fan won't move, not even an attempt.
Now thinking that the fan is starting to wear out, I hooked up my battery charger to the fan, even on the 2amp setting, the fan blows fine. Turning the motor by hand if doesn't feel like the bearings are dried out and now we know the motor is functional.
What is the next step in trying to troubleshoot this problem. I feel I've exhausted all the idea's posted on other forums. But luckily this forum has a great collection of BRILLIANT minds who love to troubleshoot.
Thanks for any positive input!

As a last resort I might just wire in a relay off the resistor pack and feed power off another 12v source, possibly right off the battery. Any suggestions are greatly appricated.

1993 jetta TD non a/c

jtanguay · « **Reply #1 on:** December 09, 2008, 02:48:53 pm »

well confirm you're getting power to the resistor pack and if you are, then just buy a new one.. or get one from the junkers. they aren't too expensive. if you're not then there might be a blown fuse, or even a bad connection/ground.

electrical problems suck!!!

passatdiesel · « **Reply #2 on:** December 09, 2008, 03:49:30 pm »

Sorry, guess I wasn't clear enough in my post. With the resistor pack, because on high speed it's full power, the current bypasses the resistors. Now the problem I'm having is even on high, i'm not getting enough power to turn the fan, it won't even struggle. Using the voltmeter, everywhere I can check, fuse panel, at the fan switch, resistor pack, I have 12 volts. Using a battery charger, I hook up to the lead coming off the resistor pack and ground off to the battery, and at 2 amps, is enough to turn the fan. What puzzles me is I show power in volts, but appears I have no current to make the fan turn. My fuse looks good, the wires coming off the fuse box are in tact, wiggling has no effect, bypassing the heater fan control has no effect either. What could be restricting the current flow that much? I picked up a relay and some wire, so I should have the fan rigged up to work, but the problem still eludes me.

Looks like this could be a possiblity, the octopus ground cluster may have been corroded. I'll check in the morning.
Incase others have a similar problem, this is the link where I found this out.

http://forums.vwvortex.com/zerothread?id=3124420

the caveman · « **Reply #3 on:** December 10, 2008, 08:01:22 am »

Just to clairfy what you are checking, the won't be any current draw showing unless it's actually working. Definitily double check your grounds .

passatdiesel · « **Reply #4 on:** December 10, 2008, 08:34:53 am »

I can't seem to find what the problem was, the ground didn't look corroded, but when it put it all together again, everything works. Sure hope I don't run into this problem again. But I would agree, based on the results I've seen, I would suspect that it was a grounding problem. However, before I took the fan apart, I ran my battery charger off the positive terminal of the fan, and the ground off the body, and the fan spun. That made me think that the grounding was adiquate. That's what really puzzles me.
I hope that if this problem occurs for something else, the steps I took to troubleshoot will be of some help. Isolate area's to confirm if they function or not. From what I've read, the most common problems would be

1. 30amp Fuse located in the #6 slot (mine was good)

2. Fan speed switch, the contacts wear down over time, just remove the plastic knob, and that will expose the contacts. Use some kneedle nose pliars to adjust the contacts.

3. The resistor pack reduces current flow for the lower fan speeds but is bypassed on the high setting. If you don't have the lower speeds, replace the thermal resistor, your local electronics or appliance repair shop will have them.

4. The wires leading into the motor themselves are soldered in place, so that shouldn't be an issue, but if you want to visually check it, there are 4 rubber tabs that protrude through the plastic shroud containing the electric motor, just manipulate them with a flat edge screwdriver and the casing should pop off.

5. What I'm assuming was my problem was grounding. The ground wire plugs into an 8 slot grounding terminal. What you can do to test for poor grounding, and what I eventually did was slide a paperclip into the female connector on the ground wire, and then ground it off to a different spot. Unless you have a high current ammeter to use.

That's about all I can think of when troubleshooting this particular problem. Hopefully whoever has this problem, this thread can help.
Good luck.

the caveman · « **Reply #5 on:** December 10, 2008, 10:35:31 am »

For some reason i thought your car was a rabbit. On those models, as you said, if you remove the heater control trim and fan switch knob you can see the contact blade. Over time they heat up and distort, and then the contacts don't touch. Next time it happens, just push on the blade to see if that solves it. It's usually #2 & 3 speeds that stop because of it, but obviously anything is possible. Also if you want to make sure the fan is really free, remove and use the Mr. Hsu test. With the housing in one hand, you should be able to EASILY turn the fan with your pinky finger, Any more resistance than that and you will burn the resistor.

Gearhead · « **Reply #6 on:** January 02, 2009, 07:14:41 am »

Are there any MK1 A/C resistor packs available anymore? Where are you guys picking these up? I'd replace my thermal fuse, but somebody already broke one of the "coils" in mine trying to fix it.