wierd ticking noise coming from below the ecm housing-97 850

brentsole · Post by **brentsole** » 30 Sep 2008, 21:13

This is my girlfriends car and I don't know too much about volvos as I spend all my time fixing my audi, but she has a loud ticking noise coming from what looks like a harness that comes out of the ecm housing. the ticking starts as soon as she turns on her cars accessories and continues after the engine has been started. I have narrowed down the noise to a strange looking rectangular harness that comes out of the bottom right of the ecm housing. does any of this sound familiar?? thanks in advance.

Post by **MadeInJapan** » 30 Sep 2008, 21:16

Welcome to MVS.
That's a new one on me. I hope someone has encountered this and can give you some information to help you with this.

brentsole · Post by **brentsole** » 30 Sep 2008, 21:38

Do you know what I am talking about though? the wire harness comes out of the ecm housing and leads to a relay above the cooling fan. Basically when the car is making the noise I can physically reach down and touch this harness and feel it vibrating. I am totally confused as to how this is happening. Totally stumped the more I think about it.

Post by **Ozark Lee** » 30 Sep 2008, 22:36

I spend all my time fixing my audi

Been there, done that, got the T shirt. I owned an Audi 5000 (Even worse I own a Porsche 944). I failed to buy the optional credit card reader on the Audi where every 60 days you swiped a credit card on the dash (15 years ago and $600.00) and the damned thing would run again.

At that time "Hans and Frans" would swipe the credit car for me ($600.00) and they smiled and it would run again.

To your original question. When you talk of a clicking sound is it more of a buzzing sound? That is the idle air controller which is totally normal. The only thing under the ECU is the window washer pump and short of making noise it shouldn't bother the cars performance.

The only other thing that I can think of that you might be describing is the cooling fan relay which is actually located on the fan shroud near the ECU/ECM box.

The ECT sensor will cause issues with the cooling fan and its relay, do you have any codes?

...Lee

mbsl98 · Post by **mbsl98** » 01 Oct 2008, 08:01

With the key in position II (on but not with engine running) you should be getting the noise, right? Open the hood and find a molded black plastic cover toward the passenger side of engine bay, to the right of battery and left of intake manifold, just back from the fan shroud. That covers the thottle plate, throttle cable, idle air valve, etc. Just put your hand on the cover and see if there is a vibration. It should be doing that, and if so, it is coming from the idle air valve just below it. That runs about all the time the key is on, and is a problem only when it stops. If you are not completely sure, remove the cover with a single torx screw and check the components below it to isolate the noise. There should be a noise from there even if it is not the one you are looking for. If that is not the noise you are looking for, then go on with other checks like the fan relay just under the top edge of the fan shroud.

brentsole · Post by **brentsole** » 01 Oct 2008, 15:43

I figured it out, her headlight wiper motor is bad and is making that wierd noise I was talking about, even when the switch isnt on, witch could be a switch issue as well, either way not critical. thanks guys I'm sure I'll be back.

Post by **Ozark Lee** » 01 Oct 2008, 19:08

That is a nasty problem to repair. There is a switch inside of the headlight wiper motor that lets it know that it is at its "home position" and it or the cam that drives it is obviously is bad in your case. I have seen threads on repairing the switch but the motor itself is a bearcat to get to.

I see the motors all the time on eBay, I need one for my son's car.

In the meantime if you want to shut it up you can snip the Yellow/Violet wire that goes to the wiper motor and tape off the ends.

...Lee