968, Rapid Clicking in Passenger Footwell When Cold

tamathumper · 11-13-2013, 08:50 AM

I've had an intermittent issue with clicking in the passenger footwell of my '93 968 when the car is cold, and recently discovered other related symptoms that might help me troubleshoot the root cause. I'd appreciate anyone's input.

The A/C worked fine all summer, and there was no clicking of any kind. As fall hit and temps got cooler, I might get a click or two backing out of the garage in the morning. Now, as the real cold weather is here (35 this morning, 29 tonight), the clicking is back with authority, up to 15 clicks per second. Also with the shortened days, I had the opportunity to need the headlights this morning and tonight, and noted a lot of missing lights.

1. It happens only when the interior of the car is very cold. It does not happen when everything warms up.
2. It clicks a lot when I hit a bump in the road.
3. When clicking (or stuck in "clicked off" mode), the lights on most of the climate control go out. Only the light on the fan control knob remains lit.
4. Pressing any climate control-related button, or sliding the up/down sliders, will momentarily engage whatever is wrong, it will click, and the lights will flicker.
5. When clicking (or stuck in "clicked off" mode with the lights out) the heat does not work. I assume the A/C does not either, but it was too cold to tell. The climate controls are effectively rendered inoperative.
6. I noted on the left side of my climate control, the clip holding the fascia plate is probably broken, as it sticks out just a tad and I could push it back in past flush.

Are we thinking malfunctioning climate control unit here?

mytrplseven · mytrplseven's Garage

Possibly. There's a couple of plugs on the back of the climate control and if I were you, I'd pull them and then drive the car under the conditions where you have the symptoms. If it doesn't clear up, I'd then check the grounds under the dash and engine compartment to see if they're the problem.

tamathumper · 11-13-2013, 01:35 PM

Thanks very much for your response, much appreciated. I'll be troubleshooting this weekend and will try that out.

Arthropraxis · 11-13-2013, 04:20 PM

My 951 did the same thing last winter. This year the first time I turned the heat on the heat was full hot 24/7 because of a broken heater clip. I think last year it was hanging by a thread letting the flaps stay cracked open confusing the sensors so the solenoid was clicking open and closed. Now that the clip is fixed the clicking is gone.

tamathumper · 11-14-2013, 02:11 AM

Interesting - thanks for the response, I'll definitely check the clip. Do you know if your climate control lights were also blinking on and off?

PorscheNut924 · PorscheNut924's Garage

Ah, I was just about to post a topic about this--my 924S is doing this exact same thing, started when it got cold this fall. Been driving me crazy. It clicks every morning for about ten miles, which is about how long it takes the interior to get really warm. I'm going to try cranking up the heat to maximum next time and see if it goes away sooner.

Odd thing, though, that makes me think my problem might be different, is that it is speed-dependent. It does not happen when stopped or under about 30-40 MPH. The faster I go, the more rapid and loud the clicking is. Any other ideas I could check out?

Arthropraxis · 11-14-2013, 08:02 PM

Quote:

Originally Posted by tamathumper

Interesting - thanks for the response, I'll definitely check the clip. Do you know if your climate control lights were also blinking on and off?

My lights weren't blinking, that sounds like a short or connector issue.

Slam · 11-14-2013, 09:33 PM

PorscheNut - your clicking is your cruise motor getting a signal from your Hall sensor on the speedo. Unplug the cruise motor in the engine compartment and it'll go away. Until you can get a good cruise brain.

Tamathumper, sorry to contribute to the hijack! So who's your favorite Tama thumper, BTW? I'm a Peart fan. And a Bonzo fan...

tamathumper · 11-15-2013, 02:49 AM

Peart, then Peart, even though he switched to Ludwig then DW.

PorscheNut924 · PorscheNut924's Garage

Quote:

Originally Posted by Slam

PorscheNut - your clicking is your cruise motor getting a signal from your Hall sensor on the speedo. Unplug the cruise motor in the engine compartment and it'll go away. Until you can get a good cruise brain.

Cruise motor? If you're talking about cruise control, my car doesn't have it...if not, I'm confused.

Arthropraxis · 11-15-2013, 06:51 AM

If the clicking is coming from under the glove box area it is going to be the servo motor for the HVAC system. Probably, clicks on when the power comes back to the HVAC controls.

PorscheNut924 · PorscheNut924's Garage

Mine is somewhere behind the steering wheel. Can't figure out if it's higher up or what. I was thinking relay but what relay would click constantly over 30-40 miles per hour for the first 10-13 miles of a drive and then get quieter and eventually stop? Every morning?

I had the heat at max today to get it warm as soon as possible. No difference in the clicking or when it stopped. But at least I couldn't hear it over the fan on level three.

Slam · 11-15-2013, 07:59 PM

Sorry, PNut (heh), I thought all the S cars had cruise. Now I suspect the speedo cable itself, perhaps, given your description of location. The one in my 83 took to howling at -30. First time I heard it it scared the crap out of me. Its first symptoms were a regular clicking (as the dying cable rotated) when it started to get colder out.

We're really off topic now...

PorscheNut924 · PorscheNut924's Garage

Oh dear. I was afraid it might be the speedo cable. I suppose I could disconnect it and drive and see if the clicking is gone.

Slam · 11-15-2013, 08:50 PM

Easy fix. Steering wheel off, instruments out, disconnect old cable and cut off the speedo end, duct tape the new cable to it and pull it through the dash. Jack up the LF wheel, remove it, remove the e-clip on the hub end of the cable, pull cable out of the hub and install hub end of new cable. Put the e-clip back on and reinstall the wheel. The hub cap may need to come off, but that's the job in broad strokes.

Not to hack on Pelican, but the cable they sold me didn't last 50 miles. Odd, cause every otiher part I've bought from them over the years has been just right.

Arthropraxis · 06:32 AM

Does a 968 have a speedo cable? My 951 has an electronic speedometer. IIRC, only the early model cars had a cable. Check this picture out of the left side of the HVAC box http://www.clarks-garage.com/graphics/hvac-2.jpg there are two servo motors on the drivers side.

Slam · 11-16-2013, 08:42 AM

No cable on 968. Design change in mid 85 to magnetic pickup on tranny.