1995 540i heater valve problems

[shogun]

connect the bulb between pin 1 and 2 and /or pin 1 and 3 of the heater valve. All wires connected = plug to the heater valve is plugged in, the bulb additionally.
When ignition and aircon is switched on, you can see on pin 1 12 volts. With this additional bulb between pin 1+2 or 1 and 3 you can now see if the control panel works.
3 pins, 1 x 12V and the other 2 for each valve is ground.
heater valves pinout Pictures, heater valves pinout Images, heater valves pinout Photos, heater valves pinout Videos - User Media - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting
Some more info from E32Fan, he is expert in electrics on E32 and also E34
Pin Outs Heater Valve and Aux Fan Switch - Bimmerforums - The Ultimate BMW Forum

[Clarksonvalley]

Shogun and all,

Here's what I get with my multimeter at the aux. water pump:

With engine running, 14.07 volts at aux. water pump, amp draw = 1.81 amps

At the water valve plug to the (not at the water valve itself) with or without the engine running:

See the attached diagram for voltage measurements. These measurements were taken with the engine running and the rotary heat control switches on full heat. I don't exactly know where to go from here. Any help would be appreciated.

[Clarksonvalley]

Shogun,

OK - looking at the wiring diagram you referenced in your last post, I'll plug the water valve back in and, with the engine running, both rotary heat switches set to max. and heater fan set to high speed, check for 12 volts at terminal #1. I'll also connect my test light between terminal #2 and ground, then terminal #3 and ground to see what the bulb does in both locations.

[632 Regal]

Make sure all 3 levers are all to the far right.

[shogun]

move the levers from cold to warm and back to see the differences in pulsations on the test bulb.

[Clarksonvalley]

Attached is a photo of my Water Valve Test Wiring. The two red lights are 12 volt Radio Shack bulbs. The red wire is 12 volt - actually 12.66 volts per my meter. The resistance thru each solenoid coil to ground is 12.3 ohms. With the engine running, fan on high speed, both rotary heater switches fully clockwise for full heat (except driver side is not past the full clockwise detent, garage temp = 63 deg. F. both lights are full on. If I rotate the passenger heat switch anti-clockwise, its bulb stays full on, no flickering. If I rotate the driver heat switch past the clockwise detent, both bulbs go out. There does not seem to be any voltage modulation taking place. I am wondering if the rotary switch module on the dash is buggered.

[Bill R.]

You won't get a voltage variation at the heater water control valves, they operate on pulse width not variable voltage. The solenoids inside the heater control valve are spring loaded when you give them a 12v supply it opens all the way, shut the power off and it closes all the way, by rapidly pulsing this voltage you can control the open time. with the heater control turned all the way the pulsing may be too rapid for you to see it on your test light.
The control module you're referring to is not in with the rotary switches on the dash, its down under the dash in front of the cabin filter and the sword if you have one. Its the furthest forward module down there right up against the firewall. If you buy a new one on the later e34's its has to be coded to your car according to the tis. I haven't seen one fail yet but i don't work on that many e34's these days

[Clarksonvalley]

OK, so what test can I perform to determine if the Water Control Valve is functioning properly. The main reason I suspect a bad Water Control Valve is the strong electrical smell (something electrical about to burn up) I get when the system is operating. I don't get this smell when I unplug the Water Control Valve. The Aux. Water Pump runs all of the time the ignition is on or the engine is running, no electrical smell with just the Aux. Water Pump running. Do the Water Control Valves open 100% with the application of 12 volts or do they close 100% with the application of 12 volts? If the voltage to them pulses, then the valve is constantly fluttering back and forth, more open when more heat is required and more closed with less heat is required. I just need to know what to look for and how to see it. I also own a Lotus Europa - it has a cable operated valve to the heating coil - life was simple before the computer age.

[genphreak]

The wider the wave form (slower the pulses) the more the valve opens. Increasing temp on the dial slows the pulse. You cannot notice the valve fluttering as it is inside the coil casing, has a lot of mass itself and is pushing against the coolant anyway.

Past the indent on the drivers side dial simply turns the 12V PWM action off, allowing the valve to open fully (turning your test light off)

Re the smell- this should make it easier to isolate your problem. Should simply be leaking o-rings (could you be describing the smell of hot coolant I am wondering? If so you just have to carefully remove the console and replace the o-rings on the heater matrix feed pipes) or it may be the controller Bill is talking about- a hairline crack causing a relay to flicker and burn out perhaps- they are easy to remove from the Right side, just above the trans tunnel behind the carpeted panel. Once you open the controller and can see the PCB you should be able to see more effects by examining the look of the PCB and its relays.

If the smell is indeed only in the engine bay, is it really the heater valve? Given they are a wear item, you might just want to buy a new one regardless as sensible insurance anyhow. The Bosch ones are cheaper than ever now ($120), and have failed on every e34 I've had and seen recently...

[Bill R.]

Here's a little better description of the heater control valves..... I personally wouldn't worry about a burning smell coming from them, they are just magnetic coils, a fuse will trip before any damage is done to anything... I suspect you're smelling something else. Genphreak your right, i had it backwards they are normally open and pulse to close.