Click click clicking under the dash

fiily · 04-16-2015, 11:30 AM

This clicking has been ongoing for years now on my 944, it's sounds like a solenoid/relay clicking like mad when the heat is on or off. I can most definately hear it down by the passenger footwell where the entire hvac unit is under the dash.

Either the fresh/circulating air flaps solenoid or the heating valve solenoid are the only 2 items down there that can click down there, right?

Thanks

massive · 04-16-2015, 11:34 AM

I get this intermittently on mine too

bobt4945 · bobt4945's Garage

I to have heard that clicking in the pass. foot well and my 89 turbo wouldn't start?

sjv · 04-16-2015, 02:46 PM

could it possibly be from your dmc unit

fiily · 04-16-2015, 05:30 PM

Quote:

Originally Posted by massive

I get this intermittently on mine too

I actually recorded it months ago and deleted it, and it's coming from one of my solenoids on the HVAC unit, have to put my stethoscope on it and see which one is making the clicks 10x's a second.

When the wife and I went out for dinner in the 944, it clicked like crazy and she said the car was going to blow up from all the clicking!

I have never heard my DME click before, just this awful 10-20-30 clicks by the HVAC unit.

If i just barely push/hold down the recirculating button, I get the click too. I can do another recording if you all want me to and upload it to my youtube acct. to determine if it's the same sound.

massive · 04-17-2015, 09:08 AM

Quote:

Originally Posted by fiily

If i just barely push/hold down the recirculating button, I get the click too. I can do another recording if you all want me to and upload it to my youtube acct. to determine if it's the same sound.

Recirculating button?

fiily · 04-17-2015, 09:29 AM

Quote:

Originally Posted by massive

Recirculating button?

Ventilation/Recirc. switch

tamathumper · 04-17-2015, 11:07 AM

My 944 did this, as well as my 968. It was the vacuum-controlled climate control solenoids. Especially on cold mornings it would at first sound like a zipper, and would also click once or twice each time I hit a bump, until the car warmed up.

I took out the climate control unit and cleaned all of the large contacts on the back, and I also reflowed a couple solder points that looked like they were too close together. The procedure is documented, with pictures, on another forum under the same username. You can probably find it by searching for "tin whiskers", which was referred to in a post in that thread.

Mine hasn't clicked once since I did that.

Best of luck!

fiily · 08:39 AM

Quote:

Originally Posted by tamathumper

My 944 did this, as well as my 968. It was the vacuum-controlled climate control solenoids. Especially on cold mornings it would at first sound like a zipper, and would also click once or twice each time I hit a bump, until the car warmed up.

I took out the climate control unit and cleaned all of the large contacts on the back, and I also reflowed a couple solder points that looked like they were too close together. The procedure is documented, with pictures, on another forum under the same username. You can probably find it by searching for "tin whiskers", which was referred to in a post in that thread.

Mine hasn't clicked once since I did that.

Best of luck!

WOW!!

Your issue is my exact issue, cold starting the car and it clicks like crazy, hit a bump clicks a couple of times.

So, just remove the control panel for the HVAC and clean it up with a q-tip and 80/20 rubbing alcohol?

I don't have tools to reflow the solder joints, but if I slide a certain person at work a 6 pack of beer, I am certain they can "find" the time to do it.

Tin whiskers, I checked it out, I don't like it, but it happens with solder joints and the amt of tin they used back in the day when making the car electronics.

Now I have to find how to remove the HVAC control unit without breaking it!

black944 turbo · 04-19-2015, 08:03 AM

Mine did this as well and then I got no heat at all. Ended up being the solonoid for the heater. If you are careful you can take it a part and clean the contact strips for the wiper arms and voila all is fixed. This is what I did on mine.

fiily · 02:25 PM

Quote:

Originally Posted by black944 turbo

Mine did this as well and then I got no heat at all. Ended up being the solonoid for the heater. If you are careful you can take it a part and clean the contact strips for the wiper arms and voila all is fixed. This is what I did on mine.

So, the heater solenoid was bad down by the hvac unit?

Are we talking the 2 white round solenoids in this picture attached to the zinc metal actuators with the vacuum hoses going to it.....the arrow pointed to them in the picture.

http://www.clarks-garage.com/graphics/968heatercore12.jpg

black944 turbo · 04-19-2015, 05:11 PM

No, mine was on the driver side and it was the servo motor that moves the flap for the heater. It was making the same noise you described.

Again if your issue is the same as mine, you can take it apart ( very gently as the top part is part of the actual electric motor) and clean it. Mine is working fine ever since I did this.

fiily · 04-20-2015, 07:14 AM

Quote:

Originally Posted by black944 turbo

No, mine was on the driver side and it was the servo motor that moves the flap for the heater. It was making the same noise you described.

Again if your issue is the same as mine, you can take it apart ( very gently as the top part is part of the actual electric motor) and clean it. Mine is working fine ever since I did this.

Will check it out, thanks much.

tamathumper · 04-20-2015, 07:31 AM

Quote:

Originally Posted by fiily

WOW!!

Your issue is my exact issue, cold starting the car and it clicks like crazy, hit a bump clicks a couple of times.

So, just remove the control panel for the HVAC and clean it up with a q-tip and 80/20 rubbing alcohol?

I don't have tools to reflow the solder joints, but if I slide a certain person at work a 6 pack of beer, I am certain they can "find" the time to do it.

Tim whiskers, I checked it out, I don't like it, but it happens with solder joints and the amt of tin they used back in the day when making the car electronics.

Now I have to find how to remove the HVAC control unit without breaking it!

You may be able to get away without reflowing any solder points - at least give them a good wipe down to remove any dirt and other "conductives" that might have formed over the years. Use some of that CRC Electronic Cleaner on the contacts on the back. It comes in a red spray can. Taking the climate control unit out isn't hard, the real trick is getting that clear plastic fascia out of there (and back in) without contributing to its inevitable deterioration. The clips on your dash ribbon that covers it might be crunchy by now, too, depending on how much your car sits in the sun.