6th Gen ('00-'05): Fan, Cruise Control, and MPG Gauge Quit Working at the Same Time
#1
10-17-2015, 12:08 PM
Fan, Cruise Control, and MPG Gauge Quit Working at the Same Time
I'm having a really weird problem with my 03 Monte Carlo SS (3.8l). Would anyone be able to help get me in the direction of trying to figure out what the problem is?
Sometimes, my cruise control, the interior fan, and the gauge on the roof of the interior (the one which tells the average MPG) all stop working at exactly the same time. When they start working again, they all turn back on at the exact same time also. By stop working, I mean the MPG gauge is totally blank and none of the buttons for the fan change anything. Changing the fan speed doesn't do anything either. BUT the light for the recirculating fan option stays on (if that matters).
This happens completely randomly. It can happen when the engine first starts or after it runs for a couple hours (driving). It doesn't matter whether the engine's hot or cold or whether or not the cruise control is on. The time it takes for everything to start working again is random also. It can be anywhere from a couple minutes to a couple hours. Also, one time it happened while it was in my driveway, so I let the car sit, engine running, just to see what would happen. After about 10 minutes everything turned back on.
I've checked all the fuses in the box underneath the head and the box by the driver's side door, and they all look fine. One time, while the problem was happening, I unplugged and replugged most of the fuses without it affecting the problem at all--not even a little flash in the MPG gauge or a little change in the sound in the fan.
A couple years ago I replaced the blower motor resistor, so I doubt that's the problem. I doubt that that part would affect the cruise control anyway.
Has anyone heard of a problem like this? Or does someone have an idea of a part that could affect the cruise control, MPG gauge, and fan at the same time?
Sometimes, my cruise control, the interior fan, and the gauge on the roof of the interior (the one which tells the average MPG) all stop working at exactly the same time. When they start working again, they all turn back on at the exact same time also. By stop working, I mean the MPG gauge is totally blank and none of the buttons for the fan change anything. Changing the fan speed doesn't do anything either. BUT the light for the recirculating fan option stays on (if that matters).
This happens completely randomly. It can happen when the engine first starts or after it runs for a couple hours (driving). It doesn't matter whether the engine's hot or cold or whether or not the cruise control is on. The time it takes for everything to start working again is random also. It can be anywhere from a couple minutes to a couple hours. Also, one time it happened while it was in my driveway, so I let the car sit, engine running, just to see what would happen. After about 10 minutes everything turned back on.
I've checked all the fuses in the box underneath the head and the box by the driver's side door, and they all look fine. One time, while the problem was happening, I unplugged and replugged most of the fuses without it affecting the problem at all--not even a little flash in the MPG gauge or a little change in the sound in the fan.
A couple years ago I replaced the blower motor resistor, so I doubt that's the problem. I doubt that that part would affect the cruise control anyway.
Has anyone heard of a problem like this? Or does someone have an idea of a part that could affect the cruise control, MPG gauge, and fan at the same time?
#2
10-18-2015, 08:34 AM
Join Date: May 2013
Location: Brockville Ontario
Posts: 3,052
It could be one of two potential problems.
First - you need a new ignition switch in the dash that you put your key into when starting the car (this is almost certainly your problem as mine needs to be replaced as it does almost the same thing except I don't have the MPG display)
Second - it could be your bcm, these are known to fail in our cars which cause weird electrical issues
I'm betting it's your ignition switch that needs to be changed, they have a connection on the back of them that gets loose over time and it sounds weird but when it's toast those are the problems you start to get, and they are periodic when they appear
First - you need a new ignition switch in the dash that you put your key into when starting the car (this is almost certainly your problem as mine needs to be replaced as it does almost the same thing except I don't have the MPG display)
Second - it could be your bcm, these are known to fail in our cars which cause weird electrical issues
I'm betting it's your ignition switch that needs to be changed, they have a connection on the back of them that gets loose over time and it sounds weird but when it's toast those are the problems you start to get, and they are periodic when they appear
#3
10-18-2015, 08:35 AM
Join Date: May 2013
Location: Brockville Ontario
Posts: 3,052
should have mentioned, when mine acts up, the cruise light on the dash comes on as if the cruise was engaged, the fan motor does not work either, then after a short period of time driving they just suddenly start to work, but the car drives absolutely normal with those exceptions
#5
10-18-2015, 11:44 AM
It could be one of two potential problems.
First - you need a new ignition switch in the dash that you put your key into when starting the car (this is almost certainly your problem as mine needs to be replaced as it does almost the same thing except I don't have the MPG display)
Second - it could be your bcm, these are known to fail in our cars which cause weird electrical issues
I'm betting it's your ignition switch that needs to be changed, they have a connection on the back of them that gets loose over time and it sounds weird but when it's toast those are the problems you start to get, and they are periodic when they appear
First - you need a new ignition switch in the dash that you put your key into when starting the car (this is almost certainly your problem as mine needs to be replaced as it does almost the same thing except I don't have the MPG display)
Second - it could be your bcm, these are known to fail in our cars which cause weird electrical issues
I'm betting it's your ignition switch that needs to be changed, they have a connection on the back of them that gets loose over time and it sounds weird but when it's toast those are the problems you start to get, and they are periodic when they appear
#6
10-18-2015, 07:02 PM
Join Date: May 2013
Location: Brockville Ontario
Posts: 3,052
All they do for the recall is put a plastic piece in, sadly you will have to purchase a new one which is kind of cheap on gm's part, but of course they are going to find the cheapest way to fix a faulty part in the first place. Our issue is a different one
#7
11-21-2015, 11:31 PM
Another major vote for ignition switch. Mine has been acting up for years now; HVAC, cruise, overhead display all stop at the same time or don't come on at all. Thanks to this thread, I bought a new ignition switch for $40 on Amazon ($96 at Advance Auto), and after less than an hour's worth of work everything is working perfectly! Granted I've only driven the car 6-7 times so far, but everything comes on right away.
Links to excellent install videos (you do NOT have to take off the steering wheel surround, only the plastic/metal kick panels and main cluster surround):
Links to excellent install videos (you do NOT have to take off the steering wheel surround, only the plastic/metal kick panels and main cluster surround):