Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E30 (1982 - 1993)

E30 (1982 - 1993)
God's Chariot. The E30 was produced primarily from 1982 through 1991. The cabriolet was the one exception which was produced through 1993.

Reply
 
Thread Tools Display Modes
  #1  
Old 06-30-2014, 08:35 AM
watbob watbob is offline
Registered User
Location: western massachusetts
 
Join Date: May 2011
Posts: 25
Mein Auto: 1988 325iC
AC Blower - mind of its own - High speed relay?

the blower in my 90 vert has a mind of its own. Initially it wont' run at any setting (so its not the resister) but after a few minutes it will kick on. Then the other day it wouldn't shut off, even once I shut off the car. Could this be the high speed relay in the power distribution box sticking? (I'm thinking this since it stayed on with the key off). If I looked at the circuit correctly only the AC and aux fan run off this relay...
Reply With Quote
Advertisement
  #2  
Old 07-01-2014, 03:35 AM
Billwill Billwill is offline
Officially Welcomed to the 'Fest
Location: South Africa
 
Join Date: Oct 2009
Posts: 520
Mein Auto: BMW E30 318i 1991
Quote:
Originally Posted by watbob View Post
the blower in my 90 vert has a mind of its own. Initially it wont' run at any setting (so its not the resister) but after a few minutes it will kick on. Then the other day it wouldn't shut off, even once I shut off the car. Could this be the high speed relay in the power distribution box sticking? (I'm thinking this since it stayed on with the key off). If I looked at the circuit correctly only the AC and aux fan run off this relay...
The high speed relay has nothing to do with the blower motor.

You either have a faulty blower speed switch or the re-circulate push switch (orange light) is faulty or air-con push switch (blue light) is faulty. These push switches do give problems.

There is a built-in thermo safety switch in series with the resistors that opens if the resistors overheat....usually if the blower motor is starting to seize up. Once the resistors have cooled down this thermo switch makes contact again so the blower starts up again. This may explain why the blower does not work for a while then suddenly kicks in but the position 4 on the blower speed control should bypass these resistors and power the blower in any case at full speed....this may point to the blower speed switch being faulty.

There is no way it should run with ignition switched off so maybe there have been some wiring changes made by the previous owner...pulling fuse 20 out should shut down the blower.

The blower should run at full speed any time the speed switch is turned to max...if not then this speed switch is the most likely suspect for your problems...you need to put a Volt meter over the blower motor and see what voltages you get across it when turning the speed switch.

If you have an intermittant bad ground on the blower motor...should be a brown wire...then the blower will work and stop working as it feels so check the ground and even add another ground from a clean chassis point.
Reply With Quote
  #3  
Old 07-01-2014, 07:11 AM
watbob watbob is offline
Registered User
Location: western massachusetts
 
Join Date: May 2011
Posts: 25
Mein Auto: 1988 325iC
Bill - I thought the same thing you did until the fan stayed on with the switch off (both blower motor and aux fan). Maybe I'm not reading it correctly, but looking at the power distribution schematics the high speed relay in K6 feeds the aux fan and normal speed blower resistor (see image below), which if it was sticking (open or closed) might cause the symptoms I'm getting. I will try to swap it out with a known good one later today and will let you know.
Attached Thumbnails
Click image for larger version

Name:	K6 relay.PNG
Views:	16
Size:	33.6 KB
ID:	449147  
Reply With Quote
  #4  
Old 07-01-2014, 11:57 PM
Billwill Billwill is offline
Officially Welcomed to the 'Fest
Location: South Africa
 
Join Date: Oct 2009
Posts: 520
Mein Auto: BMW E30 318i 1991
Quote:
Originally Posted by watbob View Post
Bill - I thought the same thing you did until the fan stayed on with the switch off (both blower motor and aux fan). Maybe I'm not reading it correctly, but looking at the power distribution schematics the high speed relay in K6 feeds the aux fan and normal speed blower resistor (see image below), which if it was sticking (open or closed) might cause the symptoms I'm getting. I will try to swap it out with a known good one later today and will let you know.
Yes swap out the K6 relay and see what happens.

I personally think that the reference in the diagram to "blower" is faulty....maybe a problem translating from German to English...there are a lot of mistakes in these circuit diagrams.

You need to have a Volt-meter handy to check where the voltage is coming from that powers up the blower motor even when the ignition is off!
Reply With Quote
  #5  
Old 07-02-2014, 05:26 AM
watbob watbob is offline
Registered User
Location: western massachusetts
 
Join Date: May 2011
Posts: 25
Mein Auto: 1988 325iC
Well, I have to agree with you about the faulty diagram. Swapped out the relay and nothing...so over the 4th when I have time I'll dig in with the multimeter.
Reply With Quote
  #6  
Old 07-03-2014, 12:00 AM
Billwill Billwill is offline
Officially Welcomed to the 'Fest
Location: South Africa
 
Join Date: Oct 2009
Posts: 520
Mein Auto: BMW E30 318i 1991
Quote:
Originally Posted by watbob View Post
Well, I have to agree with you about the faulty diagram. Swapped out the relay and nothing...so over the 4th when I have time I'll dig in with the multimeter.

Have a happy 4th July!
Reply With Quote
  #7  
Old 07-03-2014, 01:30 AM
Nick323's Avatar
Nick323 Nick323 is offline
Nick's Toys
Location: Windhoek, Namibia, Africa
 
Join Date: Jun 2012
Posts: 721
Mein Auto: 323i E30 2-door
Quote:
built-in thermo safety switch
My thermo switch stayed open.
I now rebuilt motor etc. and band-aided the thermo switch to closed again.
I would like a new one though ?
How to go about it ?

Also a happy 4'th of July from Nam
__________________
Don't take life too seriously; no one gets out alive !
1984 323 currently being resurrected from the ashes
Reply With Quote
  #8  
Old 07-04-2014, 07:45 AM
watbob watbob is offline
Registered User
Location: western massachusetts
 
Join Date: May 2011
Posts: 25
Mein Auto: 1988 325iC
still at a loss on this blower motor

ripped into everything this morning..here is what I found:
blower motor - works fine
blower switch - getting continuity in each setting - works ok
no voltage at gr/bn wire at blower switch with key on
checked all related fuses - ok
turned key on and checked power at fuses - fuse 3 no voltage, fuse 18 no voltage, fuse 19 12V, fuse 20 12V
re-read diagrams in both my service manual and the electrical trouble shooting guide. slight difference between the two related to relays in the power distribution box. Shows relay at k1 feeding aux fan and blower motor - swapped with know good, nothing doing.

still had the funny issue of the blower and aux fan continuing to run after the key was off - which still makes me think relay. It doesn't look like anyone has modified any of the wiring either...

Any ideas on what to check next?

thanks and happy 4th!
Reply With Quote
  #9  
Old 07-05-2014, 05:21 AM
Billwill Billwill is offline
Officially Welcomed to the 'Fest
Location: South Africa
 
Join Date: Oct 2009
Posts: 520
Mein Auto: BMW E30 318i 1991
OK firstly if with the ignition ON you get +12 volts on both sides of fuse 20 then you should get +12 volts at the Blower switch on the Green/Brown wire unless connector C204 pin 7 is bad.

The only way I can see the blower motor and the aux fan running after ignition is turned OFF is if there is something wrong with power feed to the Unloader relay K7...with ignition OFF fuse 19 should not have +12 volts on it....the previous owner may have modified this so that the auxiliary fan keeps running after the ignition has turned off so as to continue cooling the engine down to prevent heat soak...VW vehicles amongst others do this so you can hear the fan kick in and stert running after the owner has locked the car and walked away as the heatsoak activates the temperature sensing switch inside the radiator. So check that Fuses 19 and 20 do not have +12 volts on it when the ignition is OFF.

The only way I can see how the blower runs for a while after turning off is if it is picking up power through one of the contacts in the Dual Temperature Switch when the engine is hot...once the engine cools down a bit the temperature switches break and the blower motor switches off......once again this should not happen unless you have power on fuses 19 and 20 with ignition OFF.
Reply With Quote
  #10  
Old 07-05-2014, 08:50 AM
watbob watbob is offline
Registered User
Location: western massachusetts
 
Join Date: May 2011
Posts: 25
Mein Auto: 1988 325iC
still can't figure this one out. Checked the connection near the steering column. Wire from connector to switch is ok. No power on the male side of the connector, so either it is a shot in that wire or there is no power leaving the fuse box (I'm getting 12V at the fuse itself). So two questions:
1) Is there any where else between connector c204 and the power distribution box where I can check the lead for power?
2) I have a near matching e30 that I could swap the power distribution box with - anyone know how much of a PITA (pain in the arse) this would be? Any better ideas?

One completely unrelated item, but I'll mention it anyway....the other day the factory alarm (I believe factory - there an know aftermarket wires /lights I can see and the wire to the alarm horn is bundled together with the wiring for the outside thermometer and looks factory) went off and wouldn't stop for anything until I pulled the fuse. I've sense disconnected the alarm horn and replaced the fuse...could I just have a funky short somewhere?
Reply With Quote
  #11  
Old 07-05-2014, 11:48 PM
Billwill Billwill is offline
Officially Welcomed to the 'Fest
Location: South Africa
 
Join Date: Oct 2009
Posts: 520
Mein Auto: BMW E30 318i 1991
What fuse number are you refering to? Try flipping over the fuse box to see if there is a problem to be seen there...not too much trouble replacing the fuse box.

If you are getting power on both sides of a fuse, stick a pin through the insulation of the wire leaving the that fuse and check for power on that pin.....you can use this method to see if the wire has a break somewhere along its length...seal the pin-hole in the insulation with some glue afterwards. The fuse may also have a dirty contact where it plugs in.

Last edited by Billwill; 07-05-2014 at 11:51 PM.
Reply With Quote
  #12  
Old 07-08-2014, 06:11 AM
watbob watbob is offline
Registered User
Location: western massachusetts
 
Join Date: May 2011
Posts: 25
Mein Auto: 1988 325iC
figured it out

short answer - one of the prong in the fuse box was not making contact with the fuse.

I finally figured this out when nothing else made sense. I had continuity in all the wires from the fuse box to the blower motor and I had power at the fuse. Used a small screwdriver to bend the prong over and it was fixed. Next time I'll try that first, but in the future, if anyone wants to know where every bit of wiring is in the AC system, just ask...
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E30 (1982 - 1993)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 04:34 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms