Steel Warrior

This has been buggng me for years, a ticking noise that comes from the dash and sounds like it's behind the cabin temp sensor. I did a search "ticking", "ticking dash", etc., and couldn't find a thread that deals with it. Has nothing to do wih the fan as when I put it to the"O" position, still the tick noise. It's intermittent, some days it doesn't happen, other days for a few minutes, and then it goes away. Thanks!

Hilton

Probably the cabin temp sensor

It has a small fan and motor in there behind the vent, to suck cabin air through the sensor. Its probably the motor dying, or something stuck in there interfering with the fan blades.

Orantes

A word of warning, you cannot pull the cabin temp sensor from the front. You have to remove it from the rear.... My cabin sensor also ticked. I changed it when I removed the centre console for a radio install. Good luck.

Other posibility is a bad vacuum servo which can spring a leak and make a tapping noise. Different sound than a tick though. I also had this issue and it was a real pain to fix.

Steel Warrior

Thanks for the information, I didn't know the sensor has its own fan. What's really strange is it starts ticking a few minutes after I start her up, ticks for several minutes, and then stops. After that it might start ticking now and then for a minute or two. Maybe I'll take a shop vac and see if I can vacuum anything out from the front. The original owner had a couple kids, maybe they put something in it.

Bjbpe

This is sure a great site. I have the same problem but never thought to ask. God! I hate the idea of tearing that dash apart.

Kevin in Atlanta

Failing check valve near the brake booster?

dprantl

Does the ticking change if you move the bottom climate control slider to different positions with the engine running?

Dan
'91 928GT S/C 475hp/460lb.ft

Steel Warrior

IIRC I've tried that and it doesn't change the ticking, I had the slider to the far left the other day which supposedly is the only postion the HVAC fan isn't blowing and it was ticking.

MFranke

I had a worsening intermittent ticking problem before I fixed a couple leaking vacuum valves. I replaced the center vent actuator and the footwell flap actuator when on inspection I found tiny holes had worn into their bladders. The intermittent ticking problem went away.

MFranke

Is it a loud tick from the center vent area?

Orantes

This is what I was trying to describe with my bad "vacuum servo" suggestion. I should have probably described it as bad "flap actuator". It was a tapping noise though, rather than a ticking.

MFranke

There are some good tutorials like Dwayne's on addressing the vacuum actuators, including some upfront troubleshooting. Just one leak can mess up your whole hvac system, cause it to blow hot air and also cause the center comb flap to make an annoying ticking sound. It is a bit of a chore to get to some of the actuators but is well worth it.

Tom in Austin

Interesting post ... I've been hearing the tapping/ticking right after I shut off the engine. Then the other day i moved the bottom slider around and heard something similar. So must all be related to the vacuum system and comb flap.

Will add to the list of stuff to look at next time I get in around the console ...

MFranke

On mine the ticking started out like that - infrequent, but then it got worse such that is was almost constant and very annoying. I'm not sure exactly why it acted like that, probably low vacuum, but it went away after I rebuilt the center and footwell actuators. All vents operate nice and smooth now like they are supposed to.

ralphr1780

Looks like it's countdown clock before self destruction