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Does the sensor in the middle of my dash board have to do with the a/c temperature or lights? (2005) pontiac bonneville 3.8)

Yes sir, if you have automatic climate control in your SE, the sensor controls the air temp depending on the angle of the sun. It also tells the car when to turn the lights on.

I forgot to mention it has no automatic climate control! Sorry. My a/c was working fine then one day it just seem to be a little warmer than usual. I had a new a/c compressor in my storage so I thought I might as well use it. I changed the orfice tube, checked for leaks. Can't find the problem. Low side is about 43 and I think the high side was compatible at 210 or in that area. Friend said it all looked ok. Don't know what to do! help!

I can't speak to the A/C problem other than does the condenser look plugged with bugs or otherwise occluded? In response to your other question, in a non-dual climate control vehicle such as yours, that is only an ambient light sensor. It will have no effect on your problem.

You should probably put eyes on your airmix actuator to make sure it is functioning properly.

There is not rubbish such as leaves or obstructions on my condenser and no leaks. I'm wondering if I should just vac and refill coolant and oil.

check your cabin air filter to make sure it is not clogged up with leaves and debris and change it if you have never done so.

Good thought, but probably doesn't have a filter. I don't recall which year GM stopped installing these, but well before the 2005 model year. Also, I'm not sure if the SE ever got them unless the owner added it after the fact. My GXP didn't come with one. That was one of the first GM cheap-outs I corrected!

RJolly87 wrote:You should probably put eyes on your airmix actuator to make sure it is functioning properly.

I feel so stupid, but here it goes. I don't even know if my pontiac has automatic climate control! I don't think it does based on the different a/c face and knobs. I know there are 2 small a/c vents at the end of the counsole for the back seat. There is an air filter for the A/C after removing a compartment door located near the windshield under the hood on the passenger side and it's like new. Aluminum fittings on the accumulator hose going to the firewall (evaporator) is cold, but inside temp barely cool. No leaks in system. Has a new accumulator, compressor and orfice tube. Only thing I can think of is the condenser and evaporator. I have no diagram on how to change the evaporator core, but I know it's under the dash.

Check to see if you can change the controls to heat the interior. If you don't get heat, then the head unit for the HVAC may be faulty. I'm dealing with no heat/cooling control on the drivers side presently. I'm going to have to pull the kick panels off and look at the actuators to see if they are moving in conjunction with the controls. It could very possibly be the blend door actuator if you cannot command heat either.

Your low and high side numbers are fine, so the A/C is working, you just aren't getting conditioned air directed into the cabin without being blended with heat.

I checked the actuator under the glove box. I benched tested it and it works, but when I plugged it in before reinstalling, none of the buttons on the a/c panel moved the actuator. Now I'm thinking it's my a/c controls. I got the coldness back by resetting the flap manually and did not plug the actuator in after reinstalling it. The heater doesn't work and did not work throughout my testing. That's ok with me cause I don't use the heater, but I still would like to correct this. Would you think it might be the a/c control panel?

nos4blood70 wrote:Yes sir, if you have automatic climate control in your SE, the sensor controls the air temp depending on the angle of the sun. It also tells the car when to turn the lights on.

For the 2000 SSEI I just picked up, it seems the sensor is either unplugged or faulty as the lights are on even on a sunny day like today. I tried to control this by shutting off the delay for headlights, while in park. While it worked, once I put the vehicle into gear the headlights came right on....

Make sure your wiper lever is in the off position. If it is inadvertently on, all the exterior lights will come on after six seconds.

RJolly87 wrote:You should probably put eyes on your airmix actuator to make sure it is functioning properly.

yes, check to see if the air blend is working well, I get ac from pass but not driver - ac works great - air blend is stuck on outside air

check that first - may save you hours of wasted diagnosis on the system

ddalder wrote:Make sure your wiper lever is in the off position. If it is inadvertently on, all the exterior lights will come on after six seconds.

Wipers are off and not moving at all. It's odd, I will do some more investigating today seeing if something is actually obstructed the sensor as well. Are these known to do this?

There have been the occasional reports of these sensors failing, but few and far between. As for the wipers, GM believes that if they are on for more that six seconds, a poor visibility condition may exist and the vehicle automatically turns on your park and headlights. This operation is by design.

When you say your lights come on when you take the vehicle out of park, do you mean just the headlights (during the day), or all the marker/park lights as well?

ddalder wrote:There have been the occasional reports of these sensors failing, but few and far between. As for the wipers, GM believes that if they are on for more that six seconds, a poor visibility condition may exist and the vehicle automatically turns on your park and headlights. This operation is by design.

When you say your lights come on when you take the vehicle out of park, do you mean just the headlights (during the day), or all the marker/park lights as well?

It's all of them, and the actual headlights come on as well, not the DRL. It is baffling because the twilight sentinel is in the off position and as soon as you start the car the lights all come on as well. If I adjust the twilight sentinel and turn it on and then off it is the only way it stays off, but again as soon as it is shifted out of park, everything comes on.

So after 7+ months, I still cannot drive the vehicle in daylight (sunny days) without the headlights coming on completley with parking lights/tail lights on as well and staying on. The auto temp sensor works perfectly fine with whatever temp I set it to. I have even shined a bright light onto the Sensor that is on top of the dash. I have a few questions as I'm a little confused to as what the sensor* on the top of the dash does exactly. (*I recently bought part AC DELCO #12160947 based on what I thought/think is the sensor to fix this problem)

1) the above part #, if I swap this out, from my understanding in this current thread, it should regulate the cabin temperature and decide when to turn on the headlights (if twilight sentinel is on, and is obviously dark out);

2) what is the procedure to swap out the above sensor as I feel pulling upwards on it will break it.

Thanks!

It's not the sole component used to regulate cabin temperature but works in conjunction with thermistors (temp sensors) in several of the ducts. Cadmium sulfide photo cells under the dome determine the level of light shining onto the vehicle. Ultimately, it controls whether the daytime running lights illuminate or headlights at full intensity and the tail lights. The brighter the sun shining onto the occupants, the warmer it will feel and the more the cabin temperature will drop to compensate (as opposed to straight air temperature).

The defrost grille snaps into the dash pad. To change the part, you must pop this piece out of the dash pad. A non-marring trim tool is usually the recommended item, but a slot screwdriver will get under the edge as well. You will increase the possibility of damaging either the grille or pad though with anything that has sharp edges. The sensor twists about 1/4 turn into the grille and is removed from the underside.