problem with cooling fans not coming on

Sounds like the relay for the cooling fans is bad. This is a common problem. Removing the wire from the temp sensor puts the fans into stay-alive mode, and they run constantly as you found out. Have the relay replaced and you should be fine. As far as the AC, it is most likely related to your cooling fan problem. In order not to increase engine heat, the AC is determining that it has to stay off to keep the engine cool. Solve Job 1 and you should have Job 2 in the bag.

bull ...these cars have problem with bcm ,,,and ecm's with one car the ac compresser comes with ac off ...and over heats cooling fans will not come on !!!!!

Aflores1955, what did you finally do to fix this issue? Was it the cooling fan relay? I have the exact same issue on my Silverado, and everything you described to try, I tried and it behaves just like your car does. If you can let me know.

I too am having same issue. I have replaced all three relays, ECT, fan assy (due to one fan burnt out), had BCM and PCM checked (both good), all wiring checks good, all signals at correct places but still no fan activity except for 10 seconds every couple of minutes.

I replied to "Fan Problems" on this page you can read what I did for my 2000 imp, I replaced nothing but just cleaned contact points on fuses and relays(note that they all checked out good beforehand). My fans hadn't worked at all for two years, then voila! Might work for you.

02 impala, fan fuse kept burning out. ac fan still working but cooling fan fuse kept burning up as soon the fan start up.

#1 fan fuse blows when I turn the ac on in 2001 Monte Carlo SS

Try removing all fan relay's coat them with dielectric grease, plug them back in and this should work.

From were you replace cooling temperature sensor??if its autozone or o reilly u are having a big headache if my opinion is good 100% it would work if you buy it from the dealer cost around 40 dollars but it works

I have a 2000 malibu Ok im having almost the same problem my ac comes on when I start the car blows hot air.. for 3 min n but my fans still dont come on and slowly my ac cuts off...I dont have relay 10 or 6 would that stop it from wrking

Your a/c could possibly have a leak...check for freon leaks...maybe with soap bubbles ??? :)

09 impala fan came on high and stays on the whole time I'm driving but A/c don't work ... where is the relay switch so I can clean and electric grease and see if that works first

Make sure the PCM is well grounded. Fan and relay circuits route thru PCM to ground in order to operate. If not well grounded, fans won't operate. Check PCM ground wire- usually black/white wire- to make sure it is grounded to negative side of battery.

i agree with Kenair , check computer grounds

Had this same issue with my 04 impala and I tried all suggestions listed here with no luck. The fix was to purchase a used ECM from ebay and take to dealer and get it programed to you car. Fan Work now and also AC works.

kereynol, what did you do to end up fixing this issue? I haven't been able to fix my 2006 imp yet either with this issue.

I have a 2001 monte carlo, the fans don't come on until is almost in the red zone on the temp Guage, I've replaced the rad, water pump, thermostat, and both rad lines. Still over heats because the fans Dont turn on. How do u fix this?

First thing I'd look for is DTC's. Then check fan motors. You can "hotwire" them. If the motors work check the relays. If all that checks out, look up cooling fan relay control circuits on the web. Seems this basic problem has been happening for a few years. Also on GM's there are at least 5 inputs and 6 conditions that control operation of the cooling fans.

Almost forgot to tell you to bleed all the air from the cooling system.

I have 01 and my fans aren't commimg on and ac is not getting as cold as it should I have cleaned both boxes and different sensors and still nothing but I can take a piece of wire and put it from ground on battery to one connector on 2nd biggest relay on bottom and only one fan comes on so any help plz

If memory serves correctly; there are 5 or 6 different control inputs to the body control computer. The body computer switches the relay ground circuits on or off depending upon the various input values. If the relays are all functioning correctly, then you'll want to check the engine coolant temp sensor, the wiring from the relays to pcm, and the a/c charge level. For an '01 the freon charge should be about 2.2 lbs. Off the top I'd say that your problem sounds a lot like the a/c system needs a recharge.

Almost forgot to mention that the a/c low pressure side sensor also provides an input to the body pcm. Also if memory serves on this; low side pressure needs to be at least 40 PSI in order for the pressure switch to send the signal to pcm.

Hi are you talking about the relays in the fuse box? I'm having the same issue with mine

What year/model is the car? Relays were mounted in different locations depending on that.

Why isnt there fan1. 2 and 3 relay fuses in the fuse box?

Radiator fan motor connector, that was my issue on my 2008 impala,

How do you hot wire thr cooling fans

Use a piece of 10 gauge wire long enough to go from the ground terminal of the #2 fan relay to a good ground point. Hold end of wire to ground at #2 relay and touch other end to a suitable ground point. If the relays and fan motors are working you'll know it cause the fans will spin.

My fans not cumin on for my 2002 Chevy Impala an I put a fuse on it an sum coolent in it still not cumin on what's da problem u think

Your question leaves a lot of open ground. Why did u replace fuse? How low was the coolant level? What is the engine/fans actually doing when engine is operating? Check out the rest of this thread to get the scope of the issue.

Check you fan relay

I been having similar issues with the 2011 impala, one of my fans wont come on, I have no power coming from one of the connectors. I have replaced the relays, not sure what to do now, AC WORKS fine, just sometimes my temp goes up

You could just buy an outside Relay wire in single wire thermister 180 to 200 temp for amazon or eBay look up vids or diagrams for wiring itS easer than you think and be done if problem not found then you won’t at least blow engine or gasket before you could pay an expert to fix. Basically making your on simple setup. I did this to two of my vehicles and was dumbfounded at first but just look at YouTube vids electric fan input for old school cars.

2002 Impala. Goes to about 3/4 on the temp gauge before both fans kick in. Nothing before that temp. If I pull the temp sensor fans will stay on but lose my gauge. Changed relays and fuses, changed temp sensor, thermostat, radiator, checked and cleaned grounds that are coming off pcm wiring, cleaned ground that come off negative battery terminal wiring. Shouldn’t at least 1 fan be turning on before I hit the 3/4 mark of the temp gauge?

2005 Chevy Monte Carlo 3.4L Same problem no fans with AC on, tested all relays, fans and wiring working as intended. Missing neg ground to control relay #1 from pcm. I need help moving forward?