No Voltage to the heater valves. Where's the problem?

[Jehu]

I am reasonably sure the valves themselves are good and I just put in a new resistor. Where could the issue be? IHKA ? Heater Controls? The fuses under the hood all look OK. Is the other end of the Belden Cable from the Center Dash Vent Wheel switch accessible under the foot-well? I'm wondering if the other end of the cable came off the switch. I guess I can try an IHKA if I can find one used.. Maybe being right in the neighborhood of the welding at the gas pedal caused a problem there..

[632 Regal]

you have the heater on the highest setting right? Does the aux pump work? I hate electrical gremlins.

[Jehu]

No even with the center wheel set to full cold, dahs control dials to full cold and the AC ON its Hot,Hot ,Hot. I used one of those light bulb voltage testers on the water valve plug with the center dash vent wheel dialed full cold and there was no response ,no light so I concluded no voltage getting thru. If I am correct the wheel switch goes to the IHKA then to the harness out to the valves. Thankfully I don't have the sword , the IHKA final stage is about as easy as anything to replace,just plug in the new unit .. I just would rather target the right part... the only other parts in the system as far as I know are the dash controls and that switch at the other end of the dash tempt wheel cable..

[Paul in NZ]

No even with the center wheel set to full cold, dahs control dials to full cold and the AC ON its Hot,Hot ,Hot. I used one of those light bulb voltage testers on the water valve plug with the center dash vent wheel dialed full cold and there was no response ,no light so I concluded no voltage getting thru. If I am correct the wheel switch goes to the IHKA then to the harness out to the valves. Thankfully I don't have the sword , the IHKA final stage is about as easy as anything to replace,just plug in the new unit .. I just would rather target the right part... the only other parts in the system as far as I know are the dash controls and that switch at the other end of the dash tempt wheel cable..

have you got the ihka or ihkr?Either way with the drivers side temp set to full cold it should overdide what the ihk(x) is saying and turn on(or off) the voltage to the valves so that they close.

[Jehu]

have you got the ihka or ihkr?Either way with the drivers side temp set to full cold it should overdide what the ihk(x) is saying and turn on(or off) the voltage to the valves so that they close.


Whatever its called it is NOT the Sword.Its a black box. I thought both the temp wheel(between the center dash vents) and the dual controls each went thru the IHK? before leading to th Water Valves. Anyway I am boggled. Everything worked fine before the welding, then after it all wasn't working. I guess I'll just have to try first with the IHK? and if that doesn't fix it what next?

[Paul in NZ]

Whatever its called it is NOT the Sword.Its a black box. I thought both the temp wheel(between the center dash vents) and the dual controls each went thru the IHK? before leading to th Water Valves. Anyway I am boggled. Everything worked fine before the welding, then after it all wasn't working. I guess I'll just have to try first with the IHK? and if that doesn't fix it what next?

no just the dual wheels controls the temp,and only the drivers side overides the control unit.You feel/hear a slight click at each end (ie full hot or full cold)I guess you could try applying 12v directly to the heater valves( i am not sure which wires) to see if they then close.

[Jehu]

On my model the center wheel most definitely controls the water valves ;Open=Heat,Closed=Cold or some mix set in between by a plusing of volatge. That I get no change from Hot when dialing it to where it should close the valves and I see no indication of volatge at the pins on the plug under the hood at the valves suggests the the signal from the switch isn't being passed from the IHKA to the valves if I am understanding the pathway correctly. Weather the dials on the control unit with the vent sliders also operates the heater/water valves or operates stepper motors to allow mixing I'm uncertain.. Seems to me though since wherever the dials are and or the wheel i get nothing but hot and the valves should be good(opened and inspected,all clean) either the switch is not being moved by the wheel cable to signal the valves to close or the signal is not being routed from whereever it goes after the switch onto the valves.. since I believe the signal goes from the wheel switch to the IHKA I surmise the IHKA has failed possibly due to some unanticipated effect during welding and so I think I'll grab this (http://cgi.ebay.com/ebaymotors/BMW-IHKA-A-C-AIR-CONDITIONER-BRAIN-525-530-535-540-E34_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el1116Q QitemZ310082434860#ebayphotohosting)

[Paul in NZ]

On my model the center wheel most definitely controls the water valves ;Open=Heat,Closed=Cold or some mix set in between by a plusing of volatge. That I get no change from Hot when dialing it to where it should close the valves and I see no indication of volatge at the pins on the plug under the hood at the valves suggests the the signal from the switch isn't being passed from the IHKA to the valves if I am understanding the pathway correctly. Weather the dials on the control unit with the vent sliders also operates the heater/water valves or operates stepper motors to allow mixing I'm uncertain.. Seems to me though since wherever the dials are and or the wheel i get nothing but hot and the valves should be good(opened and inspected,all clean) either the switch is not being moved by the wheel cable to signal the valves to close or the signal is not being routed from whereever it goes after the switch onto the valves.. since I believe the signal goes from the wheel switch to the IHKA I surmise the IHKA has failed possibly due to some unanticipated effect during welding and so I think I'll grab this (http://cgi.ebay.com/ebaymotors/BMW-IHKA-A-C-AIR-CONDITIONER-BRAIN-525-530-535-540-E34_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el1116Q QitemZ310082434860#ebayphotohosting)

i am pretty sure the IHKA unit is the unit for cars with the three small horizontal wheels and the buttons rather than the three big wheels and sliders...I am also pretty sure the wheel between the vents only controls a stepper motor to direct heated air towards or away from those central dash vents.

[Jehu]

i am pretty sure the IHKA unit is the unit for cars with the three small horizontal wheels and the buttons rather than the three big wheels and sliders...I am also pretty sure the wheel between the vents only controls a stepper motor to direct heated air towards or away from those central dash vents.


Not to sound argumentative but I have seen the unit in my model when changing the Cabin Micro Filter and it is what is pictured in the ebay auction i linked above. Weather its correct nomenclature is IHKA I'll leave for BMW to say if there is another control unit beside this and the sword which looks like this maybe that's it.

[Paul in NZ]

Not to sound argumentative but I have seen the unit in my model when changing the Cabin Micro Filter and it is what is pictured in the ebay auction i linked above. Weather its correct nomenclature is IHKA I'll leave for BMW to say if there is another control unit beside this and the sword which looks like this maybe that's it.

no problems mate...whatever... GOOD LUCK WITH IT

[Jehu]

no problems mate...whatever... GOOD LUCK WITH IT


Well am I wrong in thinking this unit whatever its called has anything at all to do with the control of the heater valves? That was my main reason for asking. I assumed it was in the path. I know its called the A/C Brain but without shutting the heater valves you don't get the benefit of the A/C so I assumed it is part of it. If its not the problem then it;d have to be the dash controls wouldn't it?

[Paul in NZ]

Well am I wrong in thinking this unit whatever its called has anything at all to do with the control of the heater valves? That was my main reason for asking. I assumed it was in the path. I know its called the A/C Brain but without shutting the heater valves you don't get the benefit of the A/C so I assumed it is part of it. If its not the problem then it;d have to be the dash controls wouldn't it?

yes,brain controls the voltage(and or pulses) to the heater valves

[Jehu]

yes,brain controls the voltage(and or pulses) to the heater valves


Well one is on the way for a whopping grand total of $42.00.. they took $30 for it.. I'll report in if it worked..

[Paul in NZ]

Well one is on the way for a whopping grand total of $42.00.. they took $30 for it.. I'll report in if it worked..

if it turns out its the one for my car(IHKA) i might be interested in it....

[Claude]

Well am I wrong in thinking this unit whatever its called has anything at all to do with the control of the heater valves? That was my main reason for asking. I assumed it was in the path. I know its called the A/C Brain but without shutting the heater valves you don't get the benefit of the A/C so I assumed it is part of it. If its not the problem then it;d have to be the dash controls wouldn't it?

FYI the Bentley manual say:
"There are 2 types of heater and A/C control panel installed in E34. Six cylinder models are fitted with the 1HKR slide lever control panel.
Eight cylinder models received an automatic climate control system designated 1HKA. This systems control panel has three groups of three push buttons on the lower part of the panel and three rotary dials on the upper par of the panel"

So 1) for sure you must have a 1HKA control module (under the dash).

Now the operation of the water valves; you are right they are definitively activated / desactivated by your 1HKA control module, when the car is running +12Volts is applied directly from the battery through a fuse to the center pin of the water valve assembly, the other 2 pins of the water valves assembly are connected to the control module and the module "pulses separately a ground condition" to each water valve.

The valves are completly close (no water passing through) when a steady or continuous ground condition is applied to the water valves, if the control module pulses them with a ground part of the time, that will open the valve also part ov the time... it depend of the temperature selection you does. So when nothing is applied to the valves (no ground, no 12 V, no nothing !)... in other words if you pull of the water valve connector, the valve will be in full open condition and hot water and hot indide temp.. If you applied a permenat ground condition to each water valve (on each outside pins of the valve connector) this will shot / close them.

The Wheel in the center of the dash (upper part) has nothing to do with the water valves, it just control a step motor that control a flap that's used to mix fresh and hot air (bring stratified air they say in the book).

You are refering to a welding job done under the dash that may have been the cause of your trouble, what kind of welding job, will electric welding machine or else ?

It appear that your control module no longer work, a way the welding job may have affected it is either : a) if electric welding, the ground cable to the control module may have been affected... burn perhaps or b) the control module cabling may have been affected by heat.. some wire melt. So check closely the cable to the control module near the place where the welding job was done.

Good luck.

[Jehu]

FYI the Bentley manual say:
"There are 2 types of heater and A/C control panel installed in E34. Six cylinder models are fitted with the 1HKR slide lever control panel.
Eight cylinder models received an automatic climate control system designated 1HKA. This systems control panel has three groups of three push buttons on the lower part of the panel and three rotary dials on the upper par of the panel"

So 1) for sure you must have a 1HKA control module (under the dash).

Now the operation of the water valves; you are right they are definitively activated / desactivated by your 1HKA control module, when the car is running +12Volts is applied directly from the battery through a fuse to the center pin of the water valve assembly, the other 2 pins of the water valves assembly are connected to the control module and the module "pulses separately a ground condition" to each water valve.

The valves are completly close (no water passing through) when a steady or continuous ground condition is applied to the water valves, if the control module pulses them with a ground part of the time, that will open the valve also part ov the time... it depend of the temperature selection you does. So when nothing is applied to the valves (no ground, no 12 V, no nothing !)... in other words if you pull of the water valve connector, the valve will be in full open condition and hot water and hot indide temp.. If you applied a permenat ground condition to each water valve (on each outside pins of the valve connector) this will shot / close them.

The Wheel in the center of the dash (upper part) has nothing to do with the water valves, it just control a step motor that control a flap that's used to mix fresh and hot air (bring stratified air they say in the book).

You are refering to a welding job done under the dash that may have been the cause of your trouble, what kind of welding job, will electric welding machine or else ?

It appear that your control module no longer work, a way the welding job may have affected it is either : a) if electric welding, the ground cable to the control module may have been affected... burn perhaps or b) the control module cabling may have been affected by heat.. some wire melt. So check closely the cable to the control module near the place where the welding job was done.

Good luck.

Thanks for the information.. The welding was Electric, MIG or TIG..
I guess I had it backwards. I thought the vent wheel regulated the voltage to the valves and the control dials did the stepper motors.. anyway I'll have a chance in a couple of days when the new IHKA unit arrives to check the wires when I swap it in...I appreciate the very thoughtful detailed response,Claude..

[Claude]

Thanks for the information.. The welding was Electric, MIG or TIG..
I guess I had it backwards. I thought the vent wheel regulated the voltage to the valves and the control dials did the stepper motors.. anyway I'll have a chance in a couple of days when the new IHKA unit arrives to check the wires when I swap it in...I appreciate the very thoughtful detailed response,Claude..

An other thought, in the mean time you may do the following easy test:

- raise the connector to the water valves assembly (under the hood), with small aligator clips and wire, bring +12 V to the center pin of the water valves assembly and the same permanent ground to others (outside) 2 pins, that will keep the valve completly close al the time.

- check now if the A/C (cold air) works proprely; if it's only the cabling in between the water valve and the control module or part of the control module that drives / pulses the water valve that is affected some way the A/C should operate normally, if it does not that pin point the control module and you are waiting for an other one BUT do not neglect to check all the cabling and connectors condition to this module BEFORE doing the modules substitution.

[632 Regal]

wow I missed a lot. Sounds like if you are getting voltage to the valves and it is still hot then the valves themselves are stuck. You can rebuild them or just replace them, easier to plug in a working set.

[Jehu]

wow I missed a lot. Sounds like if you are getting voltage to the valves and it is still hot then the valves themselves are stuck. You can rebuild them or just replace them, easier to plug in a working set.

LOL , you're still missing it... Unless i can't use the voltage tester ,the kind with two spikes and a light on one, inserting them in the plug with the car on and the wheel dialed full cold which did not trigger the light
then the voltage is NOT reaching the plug as and when it should..lol..

[Jehu]

if it turns out its the one for my car(IHKA) i might be interested in it....


Well I don't know what I did exactly but i think I got it working. I took the center vent cable snap holder out and refitted in in the vent. I think I may have somehow snapped it in the wrong place and it wasn't in a position to allow the cable to move the switch but I have cool back though I still think I used to feel aboslutely no hot in the foot well and demister with all the dials and wheel set to full cold. I do feel hot from those two though I know when the heat is on they are always hot. Seems when i shut them fully i get a very,very slight bleeding of warm mixing from the dash vents and when I crack them open very slightly the center vents get colder still as though the backpressure from the segment of the airbox feeding those two vents gets in to the dash segment like the ducts don't seal fully when the demister and footwell vents are closed so cracking them reduces the backpressure. Then though the heat comes full from those two places and defeats the cold somewhat from the dash :( . I've seen that picture on sean and johans web site that seems to show that a mix is normal (i think) but i always used to be able to get absolutley frigid cold with the dash open/footwell,demister shut and all settings to cold...

I will take a picture of this unit when it arrives on the 8th Wednesday and i'll make sure it works and if i don't need it maybe you can let me know if it is the one you need.

[Jehu]

if it turns out its the one for my car(IHKA) i might be interested in it....


Paul, I tried this unit in place after i eliminated mine as a cause and it works ,it was listed as tested and working perfectly by Vines on ebay anyway. I heard they have a good repuation. If this fits your car and you need it feel free to contact me.

http://home.comcast.net/~cpkver8/images/ihka2.JPG
http://home.comcast.net/~cpkver8/images/ihka1.JPG

[Paul in NZ]

so where are you at with your heater problem?

[Jehu]

so where are you at with your heater problem?


I have response from the ceneter vent wheel now. I can not however get the valves to close fully it seems. Before this happened when I had the settings at All Full Cold and happened to open either the footwell or demister vents they were never hot,juist ambient temp,of course when I dialed in heat they would deliver hot air but now even when dialed to full cold they still deliver hot air so I have to surmise the valves aren't shutting . Wyhen i have the AC on and the demister and footwell vents shut tight with only the centerdash vents open I can have chilled air but it isn't as cold as it had been I can still detect a smidge of warm mixing with the Fan Blower of HIgh,when I crack the demister and or the footwell just a hair the center vents become slightly colder but of course the warm air comes from those when before it didn't ( with the A/C on) when I turn the fan down and shut the cracked demister and or footwell the air temp gets coldest but I then don't have the blowing nice and hard.. I gather that there is some leakage from the segment of the airbox which feeds the footwell and demister ducts when their vents falppers are shut and since the heater core is still being given coolant thru the valves even though all settings are at full cold and ac on I get this mixing which I wasn't before... Understand me? The thing is I;d probably just try a nother set of heater valves but this is already the thried set at $150 each. I bought these last april at the dealerhsip and they did say i could bring it in and if they find they've failed they;re under a Two year warranty and they'd replace it BUT The mounting points are all broekn and the water valves are basicly just snuggled in held in place by the tight fitting hoses and the aux water pump . While not jostling around all over the place I would have to wonder weather the dealership might claim that was a potential cause ( faulty installation) and then I'd have to not only pay the diagnostic charge but also buy a new water valve.. so I am juist living with it as it is now since we're coming in to colder weather and i can love with the level of chill air I get for now.. I really need to have cool air blowing in my face when I drive.. it s like an addiction,lol..

[Paul in NZ]

have you actually tried the new unit to see if it cures the problem?

[Jehu]

have you actually tried the new unit to see if it cures the problem?

Ya.i said I did that in the post above with the pics of the unit. I get the same functions with each unit installed. That I do have the same slight warm mixing with AC on using both units would suggest to me the problem is not with either my IHKA or the one i now have extra.. so while I suppose you may wonder how I can be so sure if i still think i have a problem i suppose It just doesn't seem likely if the problem I had was with my IHKA that this one would have the exact same defect resulting in identical functuon.

[Paul in NZ]

Ya.i said I did that in the post above with the pics of the unit. I get the same functions with each unit installed. That I do have the same slight warm mixing with AC on using both units would suggest to me the problem is not with either my IHKA or the one i now have extra.. so while I suppose you may wonder how I can be so sure if i still think i have a problem i suppose It just doesn't seem likely if the problem I had was with my IHKA that this one would have the exact same defect resulting in identical functuon.

agreed....so what else can cause no voltage to the valves....