Hot! heater valve won't shut down

[calmloki]

On the '93 525it it's toasty warm - which was ok in the winter, but now... Checking I find that the hot wire at the heater valve triple plug stays hot even when the car is shut off, while the 2 switched ground wires are not grounded at any heater temperature position. When I supplly a ground I can hear both solenoids clicking - I was going to just supply a ground, thus turning the flow of coolant throgh the heater core off - but with the hot wire not shutting off I'm concerned I'll drain the battery. Any ideas what's going on? Cracked solder joints in the heater control module? The heater is overpowering the AC!!

Thanks for your suggestions, Tom

[Blitzkrieg Bob]

no power to the solinoids and close when the car is running and the heater is in the off postion.

If you have power to the valves when the car is on and still get heat, the valves by be fouled, a common problem.

http://www.bmwe34.net/e34main/trouble/Heating.htm

[Paul in NZ]

i get this sometimes and ussually can solve it by turning the heater to full and then back it off a couple of times

[calmloki]

no power to the solinoids and close when the car is running and the heater is in the off postion.

If you have power to the valves when the car is on and still get heat, the valves by be fouled, a common problem.

http://www.bmwe34.net/e34main/trouble/Heating.htm

Bob, As I understand it, when the car is running power is supplied full time and the ground wires are switched - no ground, valves open, you got heat. I have two problems: Ground is not supplied at any time, and the hot wire stays hot even when the car is turned off - which could be ok, except I was going to try to supply a ground full time to shut the heaters off during the summer. If the hot wire stays hot full time and I have the ground constant and the solenoids energised the battery will go flat. When I do supply a ground both solenoids click and the AC can be felt, so I'm ASSuming the solenoids are ok in this instance.
Tom

[Blitzkrieg Bob]

then I guess it's leaves the switching side of the circuit.

I'll take a look at my car and see if a relay is switching the valves.

[632 Regal]

yep, another case of the sticky relay deal.

then I guess it's leaves the switching side of the circuit.

I'll take a look at my car and see if a relay is switching the valves.

[calmloki]

yep, another case of the sticky relay deal.

OK, I'll bite: WHAT sticky relay deal? '93 525it is IHKRIII. The only relay I see that is remotely related is #10, the auxilliary water pump relay - but my issue is that the heater valve solenoids remain on (and they test good, shutting off heat when I supply a ground to them). Issue is NOT that the aux. water pump doesn't deliver enough hot water to the heater core when the car is idling. Deciphering wiring diagrams are not one of my strong suits.
Getting too warm and I would like this problem to be resolved. Any other ideas?
Thanls Tom

[joshua43214]

I'll give it a shot.

This is what I remember. Power comes from the fuse to the watervalve, it then goes to the control panel. the control panal has a on/off switch built into it. Temp dial to zero or above,switch closed. Temp dial at max, switch open(over rides auto temp control). the power then flows to the climate control module. There are 2 internal switches, one for passenger and one for drivers side control.

The CCM looks at the requested temperature from the control panel, and compares that to the actual temp of the heater core, the CCM then cycles the power from the water valve to ground via an internal transistor, until the heater core temp equals or is slightly above the requested temp.

The water valve defaults to 'on'.

So, most likely you have one of the following;

bad switch inside control panel.

bad transistor in CCM.

something is unpluged or partialy unpluged

bad ground at CCM.

Broken wire in circuit

Since the control panel has 2 circuits pertaining to the heater, it is unlikely that it is telling the CCM to run full heat, since both the heat 'on' and the temp dial would have to fail at the same time on both sides. Also, since other parts of the system operate, it reduces the likely hood of a bad ground.

Since you don't like wiring diagrams, here is how to aproach it. Remove and unplug the control panel, with key on, make note of which terminals on the plug have 12volts. Unplug the water valve and see which ones now don't. If unpluging the module makes no change in the terminals that have 12 volts, then oyu have a break in the line from the water valve to the panel, you have already verified the water valve can be manualy grounded to close.

Plug the panel back in and turn the dial to any setting but max. Repeat same process at CCM. Now turn temp dials to max, the power should go to zero. If you have power from the fuse to the watervalve to the panel to the CCM, but the valve is not closing, you probably have a bad CCM. But comdemn it at your own risk using this method without further testing.

You can attempt to verify the CCM getting is inputs from the panel. verify that it has a good ground circuit. and check all the fuses and try to verify all power inputs as well.

Good luck, let us know what happened.

[calmloki]

I'll give it a shot.

This is what I remember. Power comes from the fuse to the watervalve, it then goes to the control panel. the control panal has a on/off switch built into it. Temp dial to zero or above,switch closed. Temp dial at max, switch open(over rides auto temp control). the power then flows to the climate control module. There are 2 internal switches, one for passenger and one for drivers side control.

The CCM looks at the requested temperature from the control panel, and compares that to the actual temp of the heater core, the CCM then cycles the power from the water valve to ground via an internal transistor, until the heater core temp equals or is slightly above the requested temp.

The water valve defaults to 'on'.

So, most likely you have one of the following;

bad switch inside control panel.

bad transistor in CCM.

something is unpluged or partialy unpluged

bad ground at CCM.

Broken wire in circuit

Since the control panel has 2 circuits pertaining to the heater, it is unlikely that it is telling the CCM to run full heat, since both the heat 'on' and the temp dial would have to fail at the same time on both sides. Also, since other parts of the system operate, it reduces the likely hood of a bad ground.

Since you don't like wiring diagrams, here is how to aproach it. Remove and unplug the control panel, with key on, make note of which terminals on the plug have 12volts. Unplug the water valve and see which ones now don't. If unpluging the module makes no change in the terminals that have 12 volts, then oyu have a break in the line from the water valve to the panel, you have already verified the water valve can be manualy grounded to close.

Plug the panel back in and turn the dial to any setting but max. Repeat same process at CCM. Now turn temp dials to max, the power should go to zero. If you have power from the fuse to the watervalve to the panel to the CCM, but the valve is not closing, you probably have a bad CCM. But comdemn it at your own risk using this method without further testing.

You can attempt to verify the CCM getting is inputs from the panel. verify that it has a good ground circuit. and check all the fuses and try to verify all power inputs as well.

Good luck, let us know what happened.

Thank you kindly - I'll post the problem when it gets found.
Tom

[Gene in NC]

Grab a simple power relay (see fuel relay),
Pick up a switched (ignition on) b+ lead to power it,
Wire thru it an aux ground from the coil ground points to a good ground, and
You will be "Good to go" until you solve the control for the heater valve. Think that's how I will rig mine tomorrow.

Not pretty but it will work.

MacGuyver would have a wire from "the grounds", with a clip on the end, lead into the cockpit where the driver could ground it as required to control the heater valve..