[jww968]

When I start my car, (94 coupe) I hear a loud clicking sound from the passenger side of the cabin. After a few minutes it slows and stops or I can sometimes stop it by adjusting the thermostat. I believe that the source is the vacuum switch that is controlling the heater control valve. I also had this same issue in my 1988 944, but it was not nearly as bad. Has anyone had this issue and if so, how did you repair it?

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[astrojeff]

I have the same clicking sound from my car. The local shop told me it was a vacuum valve # 944-65921501. He said that it was no longer available from Porsche. Did you solve your problem? I don't know if this is the same as the heater valve which is sold as an aftermarket part on multiple web sites.



Jeff

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[astrojeff]

Sunset has the part for 52.88 (from Germany - one month away). The parts diagram also lists a "heater valve" with a similar number. I don't know which it is, but it looks like the "air valve" in the picture. I took it out today to look at it. It is made in Japan and is certainly what is clicking.



Jeff

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[SILVY968]

Jeff,



Could you please post a pic of the part and the location that it came from. I have heard that noise as well and would like to check out mine as well. My parts search calls it a VACUUM CONTROL VALVE.



Thanks

Brian

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[jww968]

Go to Clarks-garage.com and look under "Heater Malfunctions". There is a photograph labeled HVAC right side that shows two solenoid valves. (Items 2 and 3). One controls the flaps and one controls the heater valve. I think that one of these is the culprit, but I have not been able to figure out which one. Jeff - is one of these your part?

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[astrojeff]

I looked at the diagram from Clarks-garage. There are two solenoids there on the right side of the unit. The one that is clicking is the lower one, in my case. This would correspond to the solenoid valve for the heating valve. They both look very similar from underneath, but I didn't take them out. The higher one would be hard to get to. The PET porsche diagram shows two number 9 valves called air valves 944 659 215 01 and one (9) called heater valve. I think it is the latter 944 659 215 02.





I wonder if this valve has been the cause of another problem which I have had for a long time: When I first turn on the AC it runs warm for a while, then suddenly becomes cold, as if there is some heat of warm air mixing with the cold air. Doesn't do it all the time. Maybe this valve is the culprit.



Also I notice that the blower runs all the time even in position 0. Is this normal or a fault of the control unit?



Jeff

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[Greimann]

[quote name='astrojeff' date='Feb 19 2006, 04:35 PM']Also I notice that the blower runs all the time even in position 0.  Is this normal or a fault of the control unit?

[right][post="16239"]<{POST_SNAPBACK}>[/post][/right][/quote]

Normal function. No problem. Speed zero is really an idle speed for the fan.

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[jww968]

I took the glovebox out tonight and it is the lower valve clicking. Part no. on the valve is 084800 1279. What appeared to be a plug connection was hot and very soft. I could not get the connection to separate. I dug into it and it looks like the valve is soldered in. I'm going to look again when I have better light, but it appears that there may be a short or at least some arcing. If so, then the valve may be OK.

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[jww968]

Porsche part number is 944 659 215 02. The solenoid is hard wired to a pigtail and both solenoids are wired to a common plug connector. I replaced mine with a used one and everything is great. Easy fix for a very annoying problem.

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[astrojeff]

Well, I changed the lower solenoid and I thought all was well, but the clicking has returned, to a lesser degree. I wonder if the top solenoid is also bad. I will have to try to listed to them closely. If the lower solenoid is still clicking, I wonder if the A/C control unit might be the cause. It seems to go away if I turn up the thermostat.



Jeff

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[jww968]

Well, I spoke too soon. Mine resumed the clicking also, but not as bad. I'm going to try to clean some grounds before I blame the control unit. I get totally lost reading the wiring diagrams, but I think the number 2 ground point is used for the temperature control.

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[astrojeff]

I checked out the clicking again today. It's the same lower (now new) solenoid. I think it must be the control unit that is sending signals to click on and off at a rapid rate when the thermostat is turned all the way down. It stops as soon as I increase the temperature a couple of degrees. It probably is the thermostat switch (potentiometer). I am thinking of ordering a new control unit. There are a couple of companies selling the Hella unit for $246.



Jeff

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[astrojeff]

Well, it turns out that there are no control units available anywhere. Apparently, Hella has stopped making them. So I decided to clean mine. I used an electronics cleaner from Radio Shack. I think that it was the thermostat control that was making the clicking by sending on off signals continously to the vacuum solenoid. The slider switches were actually the only things with any corrosion, but I cleaned everything I could. The clicking seems to have stopped, but I'll let you know if it returns.



Actually will have saved me money if that was the only problem.



Jeff

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[astrojeff]

JWW968:



Have you managed to eliminate the clicking noise? Mine has returned. I think it must be the control unit, unless the replacement solenoid was bad. But, then you had the same problem, so I doubt that. I guess I'll have to wait for new control units to be made.



Jeff

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[jww968]

I cleaned the grounds at the battery last night. I still need to clean ground point 2, but I will probably need to remove the driver seat to get to it. Mine seems to be bad when the cabin temperature is near the thermostat setting. Maybe the controller is trying to fine tune the heating valve. No clicking today - control is set on minimum temperature and outside is 85 degrees. Since this does not appear to be a common problem (except for me - I had it on my 88 944 too) you may want to consider a used controller. I'll keep you posted if cleaning the grounds improves things.

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[pors968]

jww968,



I'm in the process of replacing the lower vacuum Valve(Solenoid, under dash, Left of glove box). The same part you replaced. The connector to the vaccum switch is melted and soft. Wondering how to remove the solenoid from the wire? is it soldered? is there any trick?



Thanks,



[quote name='jww968' date='Apr 14 2006, 01:44 PM']I cleaned the grounds at the battery last night. I still need to clean ground point 2, but I will probably need to remove the driver seat to get to it. Mine seems to be bad when the cabin temperature is near the thermostat setting. Maybe the controller is trying to fine tune the heating valve. No clicking today - control is set on minimum temperature and outside is 85 degrees. Since this does not appear to be a common problem (except for me - I had it on my 88 944 too) you may want to consider a used controller. I'll keep you posted if cleaning the grounds improves things.

[right][post="19151"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[JWahlsten]

I hate to resurrect the dead, but here I go.



I currently own JWW's car and still have this issue. This is my fourth 944 variant and I haven't had this one before. Any ideas?



I'm going to begin by cleaning the grounds underneath the dash and the climate control unit. Heck I need to change the bulb for the temp readout anyway...

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[astrojeff]

Joel,



I finally fixed my clicking noise by replacing the main control unit. I was fortunate to get it recently from a member who was dismantling his dash and selling parts. I think that there was a problem in the control unit that was sending pulsed signals to the solenoid and causing it to click on and off. I tried to clean the control unit, but that didn't work.



The control units are no longer being made; although, there is at least one company repairing them at a steep price. Check around. Hella stopped making them in 2005.



Jeff

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[JWahlsten]

Thank you. Sounds like I'll be looking for a good used control unit.

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