Fan Blower Switch in Dash - Does Not Work on just Speed "4" & No A/C

[John W.]

On my 90 Golf the speed "4" suddenly does not work. It works on all
the other speeds (1-3) just not 4. Did some digging, is this mostly
likely the switch in the dash, the relay or the fan motor?

Last day or so its been really hot and I went to to turn on the AC and
noticed that no cold air was coming out nor could I hear the
compressor running. Usually the engine dips a bit when its on.

Well I went to my Bentley manual (page 254) and started looking at the
wiring diagrams. It appears that on "4" the circuit runs from the
switch through the AC relay and than down to the fan. It does not go
directly through the fan. The AC is not working either.

So that would mean the AC relay is bad? I checked the fuse above the
relay panel and it was fine. I pulled the relay out and a coworker who
is an engineer tested it and said it appears good.

So now what? Is it possibly the control head in the dash? I saw some
people mentioning that if the freon is low the compressor will not
run. Since my "4" does not work and the AC does not work I would think
its probably something both have in common like the AC relay. If the
AC pressure was low would that preclude the "4" from working?

I am not getting this. I dont think its the resistor on the blower
motor because the AC is not working either.

Thanks.

[Joseph Meehan]

Interesting tie in with the A/C.

Normally the fan speed control goes through a series of resistors in a
resistor pack mounted on the air handler (that helps keep the speed control
resistors cool) Normally the resistors are more likely to go than the
switch. In some cars the resistors are built into the switch. A failing
bearing in the blower motor can cause a high current that can burn out
resistors, so if you start having other speeds drop out, then that would be
a good indication of a blower problem.

Does you A/C work on other speeds?

--
Joseph Meehan

Dia duit

[Mark Randol]

In article <7re4b1dgi1vdes8kj...@4ax.com>, tincanman99
@yahoo.com says...

> On my 90 Golf the speed "4" suddenly does not work. It works on all
> the other speeds (1-3) just not 4. Did some digging, is this mostly
> likely the switch in the dash, the relay or the fan motor?

I don't remember. Are 90's A2 or A3? Anyway, if position 4 on the
switch goes through whatever, position 4 on the switch is still a
possibility. You may just have another problem with the AC. There's a
low pressure cutout on many systems that won't allow the compressor to
operate when there's low refrigerant. You might just be low.

On my A3 ('95), the switch needed replaced. You could tell it was going
because it was HOT. The plastic over the switch also blistered. I put
up a how-to here:

http://home.austin.rr.com/mrandol/VW/fan_switch.html

Hope that helps,
Mark
'95 Jetta GLS

[John W.]

Thanks for the info.

My 90 is an A2. I have the bentley manual. On Friday with a coworker
who is an electrical engineer we tested the switch with a multimeter.
There is current coming out of the switch on "4". My coworker things
its either the control head or the relay. He doubts its the relay
because he tested it but he said it still could be.

We also jumped the low pressure switch to see if we could get it to
engage and it would not. This leads me to beleive its definitely the
control head or relay. I am going to try to check the control head to
see if current is coming out of it.

Thanks.

[Harry]

You may want to check the switch itself with a continuity tester to see if
the high speed postion is working. Or drop in a junkyard and buy another
switch for 5 dollars or so and switch, no punn intended. The blower area is
easy to service also. I just replaced a blower on an A2, 10 dollars in a
junkyard I pulled the resister assembly out too on the junk car but did not
need it, (I think the donor was a 91 or 92 Jetta, you have to remove the
glove compartment, drop the lower tray - and bend out the dash by removing
two screws to remove the blower assembly - one on the end of the dash next
to the drop and another screw near the middle console that also has to be
removed

An interesting thing about this is that the original had a different blower.
An 88 A2. The original blower was all metal with a short rubber air-hose
coming out of the heating duct to the blower moter metal hole on the side.
That original also had foam around the blower moter. I was a bit nervous
buying the *different* blower motor replacement but it fit perfectly by
having a plastic shrouding around the motor (in leiu of the foam) with a
plastic duct molded in that fit over the hole where the original hole in the
duct that the rubber hose came from. Different but fit perfect. I had to
snip the electrical connector though from the original blower motor and
solder to the two, replacement blower moter wires as the harness was
different. Works perfect.

(this junkyard has *two* 2.0 Audi 3A engines in Audi junkers <a pull it
yourself yard> but ain't tellin' I may put one in a Rabbit I have laying
around - they have no clue at VW parts and pricing <cheap>)

Harry

[cybe...@yahoo.com]

Do you have power to the relay? This is a seperate power feed from the
first three speeds.

My 88 Jetta when I first got it, did not work in 4. Came to find out
the main feed to the relay was disconnected. Once I hooked that back
up, the blower worked in all speeds again.

JW