TheSamba.com :: View topic - 3 speed front heater fan switch no 3rd speed ?

Wed Nov 28, 2007 9:50 am

85 gl
how do i know if this is the
a) fan switch( 171.959.511),
b) resistor,

I replaced the blower motor 2 years ago brand new a unit from Dansk http://jpgroup.anet.dk

how do you use a volt meter to test the switch ???

if it is the switch I wonder if this might be a neat replacement so id have variable speed control not just 1,2 3 speeds
http://store.qkits.com/moreinfo.cfm/MX033

Wed Nov 28, 2007 12:28 pm

My vote does to the resistor pack.

Wed Nov 28, 2007 1:19 pm

If you do not have A/C you will only have a two speed fan, IIRC.

Oops, I assumed you were talking about the cooling fan, not the fan for the heater.

Wed Nov 28, 2007 1:55 pm

If you have the rear heater, you can switch the switch with it. That way you can see if it is the resistor or the switch, which, BTW, is only $12 from Van Café new. It is also really easy to change. The resistor in the blower is a PITA to change, so think positive, think switch.

Wed Nov 28, 2007 3:14 pm

iltis74 wrote: My vote does to the resistor pack.
hmm is it possible to have flakey resistor where speeds 1,2 work but 3rd speed does not ?

how do i use my volt meter to test this ??

Wed Nov 28, 2007 6:38 pm

What you are saying is exactly what happend to mine that is why i built the relay kit. I do like the variable resistor . I am going to look in to that I have'nt read the complete description to see how much current it can handle but it would be nice if it worked. anyway back to your issue if you do not have the highest speed it is your switch and here is why.. first speed goes through both resistors and it works, this means both resistors are good. second speed goes through only one of the resistors but having first speed already proves that both are good (series circuit). third speed goes directly to the blower with no resistors. it is possible that the first switch failed due to a faulty blower but since you replaced it I would assume it is just the switch.

Wed Nov 28, 2007 6:39 pm

If speeds 1 and 2 work the series resistor is OK. It's the switch.

You are talking about the fresh air fan, aren't you?

Wed Nov 28, 2007 6:42 pm

correct.

Wed Nov 28, 2007 6:54 pm

Thx 10c & fastwagens that is exactly the analysis
I was looking for funny no other post said that in such clear language

so any other variable speed switches people have tried that worked ??

I now connect the dots seeing that fastwagen also has this relay
http://www.thesamba.com/vw/classifieds/detail.php?id=531608
but with blower in good shape and no excessive amp draw I am not sure I see the need for the relay setup..
comments ?

Thu Nov 29, 2007 7:38 am

tclark wrote: Thx 10c & fastwagens that is exactly
so any other variable speed switches people have tried that worked ??

comments ?
http://store.qkits.com/moreinfo.cfm/MXA066
would this be a better long term solution
it same at the mx33 but dbl the amps 30vs15 & has a massive heat sink & they sell it in kit form with the rotary control not soldered to the board so you can mnt control in 1 location then wire the control to the std switch ...

POINT + 12 V is connected to the positive pole of the power supply 12VDC
POINT + M is connected to the positive pole of DC Motor.
POINT M is connected to the negative pole of the DC Motor.
POINT G is to be connected to the negative pole of the power supply.

hmm I cant recall how the switch is wired I assume there are +/- wires from the blower at the switch
& switch position 3 would be the + line to the blower motor & just stub out the wires from the blower for switch positions 1/2

getting + 12vc should be easy & grd would be ok I just dont want go in the dash again :(

I like this since i never upgraded the resistor when i did the blower i bypass the resistor for ever ...
and even better this device does not use a series resistor they vary the time the voltage is supplied so you dont get different amp draws
or least that how I read the write up on how to vary the speed of a dc motor

Thu Nov 29, 2007 8:59 am

That's a pretty nice little PWM unit at a reasonable price, probably cheaper than a new set of series resistors (although yours are working). I haven't had one of the OEM fan switches out to inspect it for how well it can handle current, but being that the circuit is fused at only 16A, 20A in later cars, we're not talking about the need for any heavy-duty solutions here, less than 200-250 watts. That PWM unit would give you variable speed control rather than preset speeds, which is a nifty feature, and it wouldn't be hard to wire in, just make sure it's mounted somewhere there is a little air around it so it can dissipate heat. The fan motor normally grounds to chassis, "behind air vent" according to the book, doesn't say which side, but you would have to bring the motor ground to the PWM controller as well for it to work.

The simpler solution to lowering the amps the OEM switch has to handle is just to put in one relay on the #3 speed circuit and call it a day. Fastwagens did a nice job on that triple relay setup, but with all due respect and great admiration for his diligence, the first two relays are superfluous; the series resistance lowers current flow in the circuit, so at speeds one and two the switch is handling far fewer amps, it's only at the direct power position that the amps get that high. Just do what he did on only speed three and you've taken the heavy load off the switch. That's the approach VW took on some of the other high-wattage variable speed motor items, like the AC and radiator fans.

Thu Nov 29, 2007 11:05 am

tencentlife wrote: That PWM unit would give you variable speed control rather than preset speeds, which is a nifty feature, and it wouldn't be hard to wire in, just make sure it's mounted somewhere there is a little air around it so it can dissipate heat. The fan motor normally grounds to chassis, "behind air vent" according to the book, doesn't say which side, but you would have to bring the motor ground to the PWM controller as well for it to work.

hmm that $64 question is it possible to gain access to the blower motor neg grd w/o a dash RnR ..
apart from that i dont see any down side
any body that has been into the dash more recently than 2 years and dont have alzheimer's ?
recall if there is any access to that motor grd

Thu Nov 29, 2007 11:25 am

Well, "behind air vent" says that whichever end of the dash said vent is at, access should be pretty easy. It's most likely the two rosettes forward of the left dash-end vent. But I could be way off; that's just what Bentley says.

You've been in there lately, no? What did you see?

Thu Nov 29, 2007 12:46 pm

I've got some pictures here http://tinyurl.com/3d8d8o from when I did the replacement of the heater blower. There is a couple there that show the old resistor harness. I replaced it with a fairly generic VW resistor part# 191 959 263C. I ran the wires from the new blower externally to the new resistor.

Fri Nov 30, 2007 11:14 am

Our front heater switch was acting up also
good 1 & 2 speed but no #3(max speed)
I found by slowly turning the switch almost to #3 I found the sweet spot and it runs.
The switch is made up of some flimsy small copper "switch" arms and they were not making connection until the sweet spot was found
hope your fix is as easy

keep warm
hank

Sat Oct 16, 2010 9:39 pm

I'm also experiencing a blower switch problem myself. I can get the sweet spot when I push the switch in. I've obtained a replacement switch, but I'm now having problems trying to remove the vent panel that covers the switch. Any clues?

Sun Oct 17, 2010 8:07 am

tokky28 wrote: I'm also experiencing a blower switch problem myself. I can get the sweet spot when I push the switch in. I've obtained a replacement switch, but I'm now having problems trying to remove the vent panel that covers the switch. Any clues?

Hello tokky28,

Welcome to the samba.

The plate that covers the fan switch and the control sliders is only "pushed-in". No hidden latch or other anchors. You just have to pry it off - carefully. Pictures on Ben's site, http://www.benplace.com/dash.htm, around the middle of the page.

Taking your time is the key. Good luck,

JMR

Sun Oct 17, 2010 9:53 am

for what it is worth
I ended up replacing that flimsy VW switch with one from the Volvo 240.
real heavy duty switch compaired with the vanagon switch