Hello Everyone,

I have a similar problem, but my problem is that the fan turns slowly. I posted it previously on Fixya, but did not get anything that solved it. This is what I'd written so far, including today'* post.

The radiator cooling fan works sporadically, sometimes it turns on but turns very slowly/weak, other times not at all. If I 'jumps tart' the fan by pushing it with my finger it starts turning, but slows down and stops. While it is turning, the air strength is very weak. At a stop light the A/C gets warm too. Is the fan'* strength and speed controlled by the temperature sensor? As a test, I unplugged it and used a 12V motorcycle battery to test it and it turned very strongly and fast.

Jul 12, 2013
Dave Takeshi
Hello everyone. Thank you for your solutions so far. This is my first time asking any questions so please do not worry about getting a bad rating as I believe that what is important is all of you who took time out of your busy lives to try and help me. I appreciate it a lot, even though some of the solutions do not work. Sorry about the first 2 comments above, I pressed 'enter' to make a space and it posted my greeting before I wrote the rest of my comment. Ronny, the radiator reservoir is full. I first drained the whole system as much as I could. The radiator fluid is clean and was changed not too long ago. I've always used Dexcool so there is no corrosion or plugged passages as far as I can tell. The fluid level is not the problem. The problem is the cooling fan. It works fine sometimes, and at other times it turns so slowly that I can't feel any air blowing out the back of it. Ealier in the night I started the car and let it idle until the engine temp needle was in the middle of the gauge in the normal zone. Every few minutes the fan would kick on and it seemed to be working okay as the noise from it was much louder than last night, and it was moving a lot of air out the back, as much as when I powered it using the 12V motorcycle battery yesterday. I then drove it around on roads at 25-30 mph with the A/C on, then jumped on the freeway for a bit. I then parked it with the engine still on at a park and soon the temperature climbed a little higher than normal. The air coming out from the A/C ducts got warmer, so I knew the fan wasn't turning again. I checked it and sure enough, it was barely turning. I could stop it easily with my fingers, and when I let it go it started spinning again, but very slowly. There is only 1 large fan on this model which cools both the radiator and the A/C condenser. It has an isolated negative and is not body grounded. I tried looking for the relay in the fuse box, but could not find one. I found only a fuse for the A/C fan. Can anyone help me find the location of the temperature sensor for this year make and model car so I can test it with an Ohm meter? Also, does the system just turn the fan on and off, or does some part of the system also control fan speed? If anyone can help me with those things I'd appreciate it very much. Thank you all so far for all of your help.

Jul 12, 2013
Dave Takeshi
July 13, 2013 2.29am Okay, I have identified the cooling sensor. It is located next to the waterneck on the right side of the block. I also identified the relay. It'* on the left side (front of car facing engine) near the firewall. There are 3 other relays on that bracket and the fan relay is #3 (left to right). It shares the same light blue wire (positive) that the plug to the fan has. I jumped it at the relay and the fan took off and blew full blast, which is a good thing. It means that the fan motor isn't the problem. But here is where it gets just too weird. When I hooked everything back up, I took it for a drive to get it up to its nomal operating temperature and parked it with the motor and A/C still on. As the temp rose, the fan kicked on and spun very slowy. I'd say 100 rpm if that. I could easily see it turning to the point I could count the revolutions. I used a piece of rubber and tried to stop it, and it gained power and rpm'*. The harder I tried to stop it, the faster it turned. When I let it run on its own, it slowed and almost stopped again. So I touched it again with the rubber piece and it sped up, blasting air out the back very strongly. This might indicate that the problem is something like a termistor or a load sensor that I am not familiar with. Is anyone familiar with this kind of system. As this is probably one for the experts, if you don't really understand what I just wrote, please do not reply for the sake of replying. I do appreciate the sentiment, but I do need to get this fixed for my mom and want to keep the cost down. Times are hard all around. Thanks again everyone.

Jul 21, 2013
Dave Takeshi
Hello everyone, Okay, I located and put in a new temperature sensor. I thought it had fixed the problem as the fan blew hard when the motor was on. The fan would come on 15 seconds after the car was started and blow strongly. However, yesterday I drove it and while at a red light I noticed the temperature raise slightly, then more and the A/C air got warm again so I turned the engine off for the duration of the light and started back up when it changed to green. I was next to a freeway onramp and went on the freeway which cooled the engine down from the fast moving air. When I jumped off the freeway, it got hot again. Strangely, I tried the old 'turn the heater on' to try and help cool the engine temperature, but it did not work. The air coming out of the vents were cool. It could be a plugged heater hose problem though, and it did not help to cool the temperature. Once home, I let the engine idle and popped the hood. Sure enough, the fan was once again turning slowly. Putting resistence on the fan with the soft rubber piece again made it speed up. The more resistence, the faster it spun. Is there some kind of load sensing sensor in this system? I just checked online for any similar problems in the Buick technical service bulletins but found nothing pertaining to this problem. I also noticed that one parts company offered an auxiliary fan control unit. Where would the fan control unit on this model be located? I don't think it'* the relay, as it'* just a small switch turning on a big switch.

If anyone can help me with this problem it would be much appreciated. Thank you

I'd like to also add that when I unplug the temperature sensor by the radiator neck, the fan doesn't turn on and stay on like the person who originally posted in this question.

The coolant is full when checked at both cold and warm levels, and am using the recommended coolant Dextron. I also tried last week to jump the fan at the relay (to see if it was the problem) and it turned the fan on and it ran strongly, but when I tried it later, the fan didn't turn on at, then turned on when I tried it later again. Again, it ran strongly. But when the temperature is at normal running temp and higher, the fan turns very slowly. It is not the thermostat, as it runs cool when going 25 mph and higher, and will overheat in traffic to the point the coolant boils out.

It is puzzling me quite a bit.

sounds to me like the fan is bad, they just fail that way. alot of motors fail when hot. and the fact that its fine when moving backs it up as most of the time the fan is not on if you are above 30 or so

Hello jwfirebird,

I tried disconnecting the fan'* plug and used a 12VDC motorcycle battery to see if it would work, and it does. The fan blows very strong like it should. But when the plug is reconnected and the fan is turning slowly, if I gently press a soft rubber piece on the blades, the fan speeds up according to how much pressure is applied, as if there is some kind of load sensor somewhere sensing the electrical load on the fan motor. It is my mother'* car and she'* in her 80'* so I don't want her to get stranded anywhere (again) as it has already overheated once at a shopping mall when there was a lot of stop and go traffic. There is only the one fan that cools both the radiator and evaporator for the A/C. Would you happen to know if there is something on the A/C side that may be causing this?

Thank you

I forgot to add that when I did the test by using the other battery, the temperature was above the normal operating temperature and it blew very strongly out of the back of the fan housing. Is there some way I can post a video on here? I think it would be helpful to anyone trying to help me diagnose this, and also to see how weird it is. The more pressure applied to the fan blade, the faster it turns. When pressure is released, the fan slows down again.

Thank you again

What Buick Model/Year do you have?

With most there is a primary, and secondary fan, I'd have to try to look up exact specs when I know what motor you have, but I can say with my 3800 II NA the primary comes on at like 210F, and the secondary if the AC is turned on, or if the operating temps reach somewhere around 230F

i looked at the diagram, it does show two. it says there are three relays and low gets its power from relay 1 but gets its ground from 2. then in high relay 3 comes on and changes 2 to run both. so maybe you have a relay issue

Hello WillamE,

My mom'* car is a 1997 Buick Skylark Custom with a V-6 engine. There is just a single large fan that cools both the radiator and the A/C evaporator. I even took the fan out to test it and it seems to work fine. It was the easiest fan removal I've ever done on a car. Just a single bolt at the top, and lift straight up. There are 2 points at the bottom that slip into holders to keep it in place. How ingenious this design is! Now, if only they could make changing plugs on new cars easier!

Hello jwfirebird,

Wow, that so far makes the most sense of all. I know when I looked at the top right side of the firewall, I had said that I had seen 3 relays up there, but looking carefully, there is a 4th (more toward the driver'* side) next to the other 3 that was hidden because of its darker color. I'd assumed there was only 1 fan relay there, but now that you showed me there are 3, I'm thinking that perhaps one of those might be the culprit, and not switching on when it should be, thus making the fan turn slower than it should. Would you know how I could go about testing the relays (and without buying one of those code error machines)? Is there a sequence I can follow?

Thank you everyone. I appreciate this a lot (so does mom!)

i was going by the regal in your about me info. no crazy anything not even speed control on a skylark. either the fan or the relay is bad. relays get intermittent can work sometimes and sometimes not you just have to replace it and see