Climate Control related to idling issues

[sjmcc]

Hi all,

Bit of an issue with my 95 VS Berlina (Auto, V6). At times when I am driving around, as I pull up to stop, when I sit idling the engine surges. The revs don't change (at least not noticeably) but it is as if I am gently throttling on and off, on and off. If you don't keep the brakes held on realtively forceably, the car likes to do little 2 inch or so lurches forward.

Now, this only occurs SOMETIMES when I am driving, and this appears to be related to the times that my climate control panel will work or not. Sometimes, the climate control panel will not work (i.e pressing ANY or ALL of the buttons will not get a response, the LCD screen does not light up and the unit is completely dead). When the climate control panel will not work, this is when the car decides to surge as I idle, but if the climate control is working (doesn't matter if it is running or not, just as long as it is working) the car idles fine. When the panel is working, all functions, including fan speed, AC, demisting and temperature all work fine.

I was sort of thinking along the lines of this being some electrical problem, but not sure what. I can find no pattern as to when the climate control decides to work, it can be lights on or off (or high beam), stereo on or off, or any other number of variables that I can think of being different. Sometimes the climate control will work immediately when I start the car, other times it will kick in after 15 mins, other times it still won't be working after 2 hours. Could it be that a fuse or a relay is faulty, which is causing the issues with the climate control?

More importantly, regardless why the climate control panel works intermittently, why does this play with the throttle at idle?

I'm not sure where to start with this so any help is greatly apprecaited.

Cheers

[pjdm1980]

I would do a code check first then tried to work it out from there-
Checking error codes VR/VS (Revised)
Cheers Pat

[BlackVXGTS]

The climate control panel regulates turning the air conditioner on and off. When the air conditioner is turned on the PCM/ECM uses this signal to adjust the idle speed higher (via the IAC valve) to compensate for the additional load placed on the engine. Likewise, when the air conditioner is turned off the idle speed reverts to its normal setting. Perhaps the faulty climate control panel is causing this air conditioner signal to cycle on and off causing your surging.

[SWE11L]

Mine used to do this too years ago. I didn't have the idle issues but what you've described with your climate panel is exactly the same. I replaced the climate control sensor, just got one from the wreckers swapped it with mine and it has worked fine ever since. I've attached a link to one on ebay incase you dont know what it looks like. You need to pull apart the dash around the radio/ climate panel to get to it. Hope this helps. VR VS COMMODORE CALAIS STATESMAN CLIMATE SENSOR | eBay

[sjmcc]

Hi all,

Sorry for digging up my own thread and not getting back onto this sooner, I've had a bit of a crazy month or so.

Just had the car fixed up a fair bit mechanically (engine out, oil/water leaks fixed, tps switch replaced and much more) and so now I am determined to fix this up.

My mechanic friend of mine said that my issue is almost certainly as BlackVXGTS described so +1 for you.

I am going to try to systematically work through my climate control to fix this up as driving without a demister at 6:00AM in Melbourne is not cool, nor safe.

Thanks for the tip SWE11L, I will look into either servicing that part (as is described in other posts) or getting a new one.

I have also read in other posts how to do the diagnostics check, not sure if it will work given that I can't get my panel to display anything most of the time but I will give it a go.

Cheers all

[Vee-ard]

You need to really push hard on the brakes or just a bit more than you normally would? Maybe a vacuum leak to the booster.

[wamboin23]

check out the 'check lamp' relay in the fusebox under the bonnet.

climate control gets its power through this relay and it is common for it to cause issues. its not the relay itself, but the connectors in the relay base. over time with vibration etc the connectors move apart and create a bad connection. pull the relay out, and using something long and thin, gently retension the pins.

may have something to do with the idle aswell, as this relay, when turned off will earth a circuit to the PCM to tell it the engine is been started.

[sjmcc]

Well I FINALLY got my work sorted out and re-conditioned my VAC solenoid box today, as described in this thread :VS Climate Control Problems.

So far it seems to be working fine, so I will give it a week or so before I say that it's fixed, but so far so good.

If it doesn't fix it I will have a look at the relay issue described wamboin23 so cheers for that.

And a note for anyone looking to pull out their vac solenoid box: Getting the vaccuum hoses back in requires LOADS of patience. Be prepared!

[Cracka]

lol I think I reco'd my whole unit in under 30 minutes :P