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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.

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  #1  
Old 11-20-2013, 07:22 PM
Colin W Colin W is offline
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K5 and K7 relay issue

Hello everyone,

Blower motor comes on randomly, and usually only when the engine is turning over (to start). Once it starts, it turns off again. Sometimes it will randomly come on when I'm driving, or when I turn the key on.

The starter has a napa sticker on it so it's obviously been replaced. I know it has to do with grounding on the solenoid, but can someone help out exactly what is wrong? I have seen other threads where people suggest something about a green and black wire, but all of my wires are mostly black with one thick, red wire.

Oh and the coolant light will randomly come on sometimes even though the coolant is fine.

Someone help me out!

Colin

Last edited by Colin W; 11-20-2013 at 07:24 PM.
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  #2  
Old 11-20-2013, 10:20 PM
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hornhospital hornhospital is offline
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You titled your posting "K5 and K7 relay issues". The K5 and K7 relays are load reduction relays. Their only purpose is to temporarily disable various electrical devices while the engine is being started. I do not think the problem with the blower motor has anything to do with the "unloader" relays. If you believe they do, just pull one out and start the car. If the blower motor still comes on during cranking, put that relay back in and pull the other. Repeat the cranking test. I think you'll find it makes no difference. IF it does, replace the relay that, when removed, returned the starting to a "no blower motor running" condition.

The low coolant light occasionally coming on is a common problem. If the coolant level is normal, the float in the level sensor is waterlogged, broken, or the sensor itself is bad. It's nothing but a float with a magnet on/in it, and the sensor has a reed switch in it. When the float drops, the reed switch closes and triggers the warning circuit. Replacement coolant level sensors are available. They aren't terribly expensive, and for something as important as the cooling system, I'd replace it.
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  #3  
Old 11-21-2013, 01:27 PM
Colin W Colin W is offline
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From my reading online, the k5 and k7 unloader relays control the blower motor and various other things. My issue has something to do grounding on the solenoid. The relay's are fine, but it is all part of the circuit.
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Old 11-21-2013, 08:25 PM
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hornhospital hornhospital is offline
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Did you try what I suggested, or just read on line?
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Quotes to live by:
guessing gets expensive...drivinfaster
nothing is more expensive than a cheap BMW...c4harpe13

Ken Kanne, Silverhill, AL, E36 Forum Mod/Craigslist addict/Hoarder of all sorts of stuff
BMW-CCA #441426
1995 318is "Bebe"; 1993 325is "Elvira" 1985 635CSi "Katja" 1984 633CSi "Sylvia"
HAVE I HAD MY MEDS YET?

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  #5  
Old 11-22-2013, 04:10 AM
Billwill Billwill is offline
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There are many things that could cause the blower motor to run and not run.
It picks up its power from unloader relay K7.....if you remove this relay and jumper out pins 30 and 87 in the K7 relay socket it takes the unloader relay and its "grounding" out of the question as the blower should run when turned on whether or not the engine is being started at the time.

More likely is that the blower may be faulty or starting to seize up....there is a thermo-switch on the resistors to the blower that breaks the circuit if the resistors get too hot...this normaly happens if the blower is drawing too much current and needs replacing.

If the blower does work fine with pins 30 and 87 jumpered together then there could be a problem in the starter motor area....ie. a bad section on the comutator ring.
The unloader relays normally get +12 volts on the one side of the coil and the other side of the coil goes onto the one brush of the starter motor usually via a Black/Green wire. The unloader coil is efffectively 'grounded" through the starter motor as long is the solenoid has not been activated....when the solenoid is activated this brush on the motor gets full +12 volts on it so the K5/7 relays drop out because of having +12 volts on both sides of their coils. So it is theoretically possible that after starting the engine the starter motor stops in a position that has a bad segment on the comutator ring so the blower stops working....when next trying to start the engine though it would not start as the brush is on a bad segment....so I doubt your problem is in this area....more likely a loose connection somewhere or an overheating blower, or your orange "recirculate" switch or your blower speed control switch!
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  #6  
Old 11-22-2013, 11:37 AM
Colin W Colin W is offline
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Lets try to narrow this problem down further:

The blower motor seems to randomly come on, usually after messing with it (pulling the relay and wiggling the wires on the solenoid).

Before a drive with the car yesterday, I messed with it a bit. The blower motor didn't come on until the car was started. Once it was started it, the blower motor came on. I decided to test it while it decided to work. I pulled the relay and fuse at separate times, the blower shut off in both cases (as I'd expect, but I'm surprised it came back on when I plugged them back in). This (to me) means the relay and fuses aren't the problem in the circuit. The blower motor also worked in all stages (0, 1, 2, 3, 4) which makes me think the switch and resistor isn't the problem either. The blower motor seems to work great when it will actually turn on.

My best guess is this has something to do with the grounding on the solenoid. The starter has a napa sticker on it, so obviously the last owner replaced it.

**Please excuse my poor grammatical skills in this post; my time is limited right now.**
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  #7  
Old 11-23-2013, 12:16 AM
Billwill Billwill is offline
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As I stated if you jumper out pins 30 and 87 in the K7 relay socket you eliminate the solenoid/starter motor completely.

Have you checked the grounding on the blower motor itself...grounds can get corroded or loose.

My circuit diagram shows that it is a Brown wire on the one side of the blower going to ground at G200 but you can add your own ground to any clean chassis point....you can never have too many grounds!
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  #8  
Old 11-23-2013, 01:21 AM
Colin W Colin W is offline
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Can I just run a wire from 30 to 87 in the k7 relay or do I have to put male ends on the ends of the wire like the relay has?
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  #9  
Old 11-23-2013, 04:47 AM
Billwill Billwill is offline
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Quote:
Originally Posted by Colin W View Post
Can I just run a wire from 30 to 87 in the k7 relay or do I have to put male ends on the ends of the wire like the relay has?
Male ends would be nicer but just as a short-term diagnostic you can firmly press some wire into the female socket sections....I normally use a piece of resin-core solder...you can compress the ends to fit firmly but not too tight.

Be careful that you do not open up the socket pins as you will have bad relay connections afterwards.
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Old 11-23-2013, 11:28 AM
Colin W Colin W is offline
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Well I put a wire into the 87 and 30 pins within the k7 relay. Unfortunately the blower motor still didn't come on! Does that mean that the starter solenoid is grounding fine? Where should I go from here?

Thanks for the help,

Colin
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  #11  
Old 11-23-2013, 11:44 PM
Billwill Billwill is offline
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Quote:
Originally Posted by Colin W View Post
Well I put a wire into the 87 and 30 pins within the k7 relay. Unfortunately the blower motor still didn't come on! Does that mean that the starter solenoid is grounding fine? Where should I go from here?

Thanks for the help,

Colin
You need a meter to see where your voltage is going missing...you should get +12 volts all the way from the fuse 20 to the top of the Blower Motor when the speed control is set on "high".....this is with the black lead of your meter on a good chassis point or the negative of the battery.

If you do get this +12 volts all the way to the top of the Blower Motor....move the black lead of the meter from chassis and put it on the other side of the blower motor...if you do not get +12 volts like this right across the motor then your "Ground" at G200 has gone missing...maybe through connector C204.

Here is a circuit diagram from a 1989 325i/325is.

Sorry it is sideways....turn your computer screen on its side.
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  #12  
Old 11-24-2013, 02:03 PM
Colin W Colin W is offline
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Thanks for the help. I'll have to check this all out when I have more time. Where is G200 and C204 located? I think G200 is somewhere under the dash, but I'm not sure. Also, would either of these result in the blower motor randomly coming on when the car is starting (turning over)? I've read online that the blower motor comes on when the motor is turning over because something gets energized on the solenoid. I'm not sure what to think, but the blower motor just randomly comes on when I mess with it sometimes.

Colin
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  #13  
Old 11-25-2013, 03:41 AM
Billwill Billwill is offline
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Quote:
Originally Posted by Colin W View Post
Thanks for the help. I'll have to check this all out when I have more time. Where is G200 and C204 located? I think G200 is somewhere under the dash, but I'm not sure. Also, would either of these result in the blower motor randomly coming on when the car is starting (turning over)? I've read online that the blower motor comes on when the motor is turning over because something gets energized on the solenoid. I'm not sure what to think, but the blower motor just randomly comes on when I mess with it sometimes.

Colin
The blower motor and other non-essential items like air-con, heated seats, electric mirrors etc. are all deliberately turned off while the engine is being started so that full power is available for the starter motor...if you were stalled on a railroad track at a level crossing with a train bearing down on you then you would want the engine to fire up easily....who cares about air-con etc. at that time.
That is why the k5/k7 Unloader relays...which are normally energized while the engine is running....supply voltage to all these items. The top-end of the relays have +12 volts on them as soon as the ignition is turned on and the lower side of the relay gets its earth through the one brush on the starter motor. The rotor coils of the starter motor are thick copper wire so while the starter motor is stationary, the unloader relays pick up earth through the windings on the starter motor relay....enough current to energize the two relays but not enough current to try turn the starter motor.

When you turn the ignition key to start, a lead from the ignition...usually a Black/Yellow wire.....energizes the solenoid and a large contact inside the solenoid joins up the thick cable from the positive side of the battery to the starter motor brush....where the k5/k7 relays are also attached, usually through a Black/Green wire. So now the two relays have +12 volts on both sides of the relay coils so the relays drop out.

So under normal circumstances if you actually observe these two relays you would see them energized with ignition on, suddenly drop out as the starter motor is rotating, then re-energize and stay that way while the engine is running.

So your solenoid should have two large connector studs with 13 mm nuts on them...one has the thick cable going to the positive side of the battery and the other stud goes to the starter motor brush....the other starter motor brush goes direct to earth.

There should also be two other small connectors...either small screw-on types with nuts or small push-on connectors. The one wire, usually Black/Yellow carries the +12 volts from the start position of the ignition switch to the coil of the solenoid. If you are not sure which of the small wires is which, dissconect one and see if the solenoid energizes when starting...if everything is dead then that wire you pulled off is the Black/Yellow one and you can put it back.

The other thin wire then is the wire that connects to the lower side of your k5/k7 relays. This wire on the one small connector is connected internally inside the solenoid to the large lug that goes to the motor brush....not the lug that has the thick +12 volts wire from the battery. It is possible that this internal connection has an intermittant break in it. Sometimes you may have a non OEM solenoid that does not have this extra small lug on it for this Black/Green wire to attach itself. In this case you need to cut off the small connector on the wire and attach a large round connector onto it so that you can attach it onto the one large lug...the one without the thick positive lead attached.

So maybe you need to try this....find the thin lead that is not the one responsible for energizing the solenoid. Cut off the small connector on this lead and strip back about an inch of insulation and make a loop in the exposed wire and screw this onto the large lug...nearest to the engine block...the one without the large positive wire attached. Normally this connection is made inernally inside the solenoid but as I have said maybe this internal connection is suspect. The pirate solenoid that I have in my E30 does not have this second small connector fitted so I have had to do this procedure of connecting the Black/Green wire directly onto the one large lug.

Give this a try and see if your k5/k7 relays are now behaving as they should..if not then you need to trace this thin wire all the way to the two relays to look for an intermittant break. If the two relays are behaving properly but the blower motor is still not working then you need to trace the +12 volts all the way from the relays to the one side of the blower motor and check that the other side goes to a good chassis ground.

That is how it works...a bit long winded....but fortunately I am retired now and have much too much time on my hands!
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Old 12-09-2013, 03:34 PM
Colin W Colin W is offline
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I'm becoming a bit dumbfounded here...

I haven't had much time to get my 325iX in the garage and mess with the blower motor issue. I recently found some time, and I still can't figure it out. I pulled the blower motor cover off and the motor/resistor look brand new. They both function great when the blower motor randomly decides to work. I know the blower motor and the resistor are NOT the issue. I figured it may be a ground on the blower motor. I removed the ground, attempted to clean it, and then reinstalled it. It did look fine from the get go though (not crusty or anything). Blower motor still decided not to work.

I removed relay k7 and pinned 37 and 80 with a wire. The electronics all came on in the dash, but the blower motor still refused to come on. I was told that the wiring on the starter/solenoid has no effect when 30 and 87 are pinned together. Is this true?

I suppose it could be the c204 or g200 grounds, but I don't know how to tackle that. Where should I go from here?
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Old 12-10-2013, 12:33 AM
Billwill Billwill is offline
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Quote:
Originally Posted by Colin W View Post
I'm becoming a bit dumbfounded here...

I haven't had much time to get my 325iX in the garage and mess with the blower motor issue. I recently found some time, and I still can't figure it out. I pulled the blower motor cover off and the motor/resistor look brand new. They both function great when the blower motor randomly decides to work. I know the blower motor and the resistor are NOT the issue. I figured it may be a ground on the blower motor. I removed the ground, attempted to clean it, and then reinstalled it. It did look fine from the get go though (not crusty or anything). Blower motor still decided not to work.

I removed relay k7 and pinned 37 and 80 with a wire. The electronics all came on in the dash, but the blower motor still refused to come on. I was told that the wiring on the starter/solenoid has no effect when 30 and 87 are pinned together. Is this true?

I suppose it could be the c204 or g200 grounds, but I don't know how to tackle that. Where should I go from here?
With pins 30 and 87 jumpered out in K7 socket the heater etc. should work.

You need to trace the wiring with a voltmeter from the Blower motor all the way back to see if you have +12 volts relative to ground at the motor and if not then where is it getting lost, refer to the circuit diagram I posted

Last edited by Billwill; 12-10-2013 at 12:34 AM.
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