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View Full Version : Mk1 heater blower motor not working...



trip permit
2012.02.11, 23:26 PM
1980 VW Caddy (non a/c) - Heater motor was working fine until it randomly cut out today. Heater core was swapped last week... Car was driven a few hundred miles with the heater on at times since swap.

What should I check for? I already checked fuses. Its dark out so I didn't really get to look at it all too much. What typically goes wrong with mk1 heater systems? The blower motor still spins freely... Do the resistors go bad on them?

Any help is appreciated. :beer:

Rabbit 16v
2012.02.12, 10:53 AM
pin #D19 in the blue plug on the back of the fusebox. Has a black/red wire going to it. It is likely melted.

trip permit
2012.02.12, 13:07 PM
The black/red wire in the corner of the blue plug doesn't exist. It was snipped a while ago (can see about 1/2" of the wiring coming out of plug) by a previous owner apparently...

Iroczgirl
2012.02.12, 13:13 PM
So is the switch wired directly to power?

trip permit
2012.02.12, 13:15 PM
That is a good question. Dash has yet to be pulled off, but judging by the wiring I have seen so far... :(

An tach was also tied into the heater wiring because that died as well.

trip permit
2012.02.12, 13:32 PM
Blower motor still works in all 3 speeds (jumped it to test). Had a brand new switch, threw that in and nothing...

So I need to trace back that power wire and see what is up. Wonder where my test light went? errr!

Iroczgirl
2012.02.12, 13:38 PM
Hopefully they just grabbed power from the back of the fuse panel. One of the male spades on the back that have power with the key on.

trip permit
2012.02.12, 14:42 PM
Hopefully they just grabbed power from the back of the fuse panel. One of the male spades on the back that have power with the key on.

I think I traced it back.. And sure enough there is a wire running to a male spade that is black/red with an inline fuse poorly added. Which melted as well. While digging around I removed this:

http://a8.sphotos.ak.fbcdn.net/hphotos-ak-snc7/418785_383168838363678_100000116962368_1687053_969 614218_n.jpg

And there will be more as soon as I go pull this tach he installed. :banghead:

trip permit
2012.02.12, 15:28 PM
Still stumped on this...

I found a black/red wire that I thought was it. It was butt connected and a mess, so I removed the mess and hooked it back to where it was on the fuse box. Still nothing. How often do the resistors go bad? If I touch a wire off the battery to each wire off the resistor it will power up the blower motor in different speeds.

Need to get a test light and or volt meter before I go any further. :beer:

buddylove
2012.02.12, 16:04 PM
Just get cheap ones from Harbor Freight. My volt meter from there works great.

Iroczgirl
2012.02.12, 16:46 PM
I found a black/red wire that I thought was it. It was butt connected and a mess, so I removed the mess and hooked it back to where it was on the fuse box. Still nothing. How often do the resistors go bad? If I touch a wire off the battery to each wire off the resistor it will power up the blower motor in different speeds.


If it still does that then the motor and resistor are fine.
The black/red wire should go to your fan switch.
From the switch there should be a white wire going to the blower resistor = speed 1
Then yellow/black = speed 2
And Yellow is speed 3

Try putting power to each wire going to the blower motor resistor and see if you have all speeds.
You must also have a good ground (brown) but I suspect that's in order as you said the motor still works.

The switch could just be bad...

trip permit
2012.02.18, 22:05 PM
Update/Fixed: Black/red wire was cut from the blue plug in the fuse box and ran who knows where. I connected it back up to the fuse box and all is good again.

Funny story about on the way to fix the truck (Copied from my FB)..

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/395968_388026581211237_100000116962368_1699517_185 9884335_n.jpg

cop: "Do you know fast you were going sir?"
me: "No sir actually I don't" As I look at the cluster sitting on the passenger seat.
cop: "haha, get that fixed and go with the flow of traffic."
me: "will do, have a good day sir"

Well that was nice to get a friendly cop for a change. Good times in the caddy continue...

unimogken
2012.02.19, 01:59 AM
Haha that happened to me about 20 years ago when I was testing the engine in my old El Camino. I was driving around Redmond with no dash, no cluster, no seats or interior! I was sitting on an ammo can on its side. . . . Hehe

The Officer told me to be safe and get it home to get it fixed. He also laughed and said. . . ."at least you're wearing your seat belt!" Haha

Rabbit 16v
2012.02.19, 15:49 PM
if you connected it to the blue plug, you should remove it and relay that shit. otherwise you will have the melties..

Iroczgirl
2012.02.20, 18:26 PM
Haha that happened to me about 20 years ago when I was testing the engine in my old El Camino. I was driving around Redmond with no dash, no cluster, no seats or interior! I was sitting on an ammo can on its side. . . . Hehe

The Officer told me to be safe and get it home to get it fixed. He also laughed and said. . . ."at least you're wearing your seat belt!" Haha

Yeah, the speedo in the '55 isn't hooked up either, nor is the cluster screwed down.
So if I get pulled over I just grab it right out of the dash :lol:

trip permit
2012.02.20, 18:37 PM
if you connected it to the blue plug, you should remove it and relay that shit. otherwise you will have the melties..

It isn't connected to a blue plug. Currently its connected to the fuse box on one of the tabs connected to ignition. Thinking I am going to add an inline fuse however.

Rabbit 16v
2012.02.20, 20:02 PM
Put it on a relay and be done with it. Use a relay kit that has the fuse integrated. Bosch PN# WR-1