View Full Version : Cluster problem or am I running hot?

07-15-2007, 01:55 PM
I have a 89 SC and I have cone air filter down by the fog light. I installed new water pump, 180 thermastat, new temperture switch, and flushed the system and filled it up,and got all the air out. My problem is now the gauge goes up to the 'R' on NORM and the 'Check Gauges' light goes on. The fan kicks on and when the gauge goes back to 'N' the 'Check Gauges' light goes off, and so on repeating that cycle during normal driving. Just wondering if I need new radiator cap, or cluster problem, or am I running hot?

07-15-2007, 04:39 PM
If the check gauge light is coming on and you think its related to running hot, I would be concerned as you are running very hot. The check gauge light is actually controlled by the EEC by measuring the temp from the ECT sensor... nothing to do with the gauge sensor on the tstat housing that drives the gauge.

Unless you can control the fan on temperatures either manually (NOT recommended) or automatically with a chip, then get rid of that 180 tstat and run a stock temp one. Also, double check you have an air dam under the bumper. Things like washing out the a/c conensor from back to front also helps with better air flow. Also run a 50/50 mix of coolant with a bottle of water wetter.

Do not ever trust the temp gauge in the cluster. Get yourself an aftermarket temp gauge that is accurate. I've seen cases here where a car is boiling over when the gauge was on O and other cars it could hit red before boiling over.

07-16-2007, 12:53 PM
Thanks for the advice, but I have a question. If I install the stock 190 something tstat will it turn my fan on sooner? I don't have the air dam so what would be the alternative? And in detail how and why do I clean the a/c condensor? Thanks Again.

07-16-2007, 04:49 PM
A new cap and a 190 thermostat

07-16-2007, 09:07 PM
The fan on temps are set so the low speed comes on at 220 and shuts off at 217, while the high speed comes on at 227 and shuts off at 225.

What the 197 will do is close enough to allow time for the coolant to release its heat before its flowed out of the rad. Our rads are simply too small to support continuous coolant flow that a 180 will cause. Now if you can get an EEC Tuner or an SCT chip, then the fan on temps can be set alot lower to support the 180 so your operating temps stay well below the 220 etc.

Some folks have had luck using an air dam from a mid 90's pontiac grand am (I believe). I actually built my own using some conveyor belt I got from work. Our cars need these to keep cool while highway driving, because we don't have a big opening in the front for the air to flow in.

For cleaning the a/c condensor, you'll need to drain and remove your rad, then get a garden hose and start spraying from the engine bay forward. Keep on going until you only see clean water coming out, then keep going some more. You'll be amazed just how much crud does come out.

07-17-2007, 10:13 AM
The CE light is controlled by this stupid little circuit board mounted on the side of the cluster. You could yank it out if you feel so inclined. Swapping to a hotter thermostat wont fix the problem, the 180 should open early enough. Do you have a friend with an noncontact thermometer? I would have him check your engine at temp and get a rough reading. You might just want to throw some water wetter in there and see if it smooths things out.

What kind of coolant are you running? (50/50 60/40, water?)
When were the HGs done?

Another note, the little circuit board has 2 or 3 pots on it. I think they are for adjusting when the CE light triggers. I have a spare cluster at home I will take a look at tonight and let you know.

07-17-2007, 10:55 AM
is your fan clutch or electric? if its an elec.. maybe the low speed on your fan is toast... letting it get to the high temp before kicking on... could be your ircm... expand on your type of car...

07-17-2007, 01:09 PM
Thanks for advice. I failed to mention that alot of SC and TC guys have always said that my engine seems to be so hot, but I never had a problem. About 3 months ago my water pump went out and I changed it and the tstat, flushed rad, and new top and bot rad hoses. The gauge never even got passed the blue line before the norm range sense I bought the car. So last week I figured I would change the temp sensor on the tstat housing. this is when the 'Check Gauges' light started to come on and the gauge goes up to the 'R' or 'M' before the fan comes on. I have always used Prestone 50/50. The H/G's were done about 35K ago before I bought it. The fan is electric mounted on the rad. As for the car, I have the cone filter running down to the fog light area ( passenger fog light removed ), new exhaust 2 1/2 inch pipes from exhaust manifolds to the back were I have 2 Flowmaster mufflers. No cats or resinator. The clutch needs to be changed soon. It gets a little spongey in bad traffic situations. The car is pretty fast for dam near stock and has 137K miles. It runs 14.2 to 14.7 at 102-105mph at the track with bald radial tires at 18 psi. Of couse with no speaker box, spare tire, or tools in the trunk. I love this car and don't want to blow it up. It's also my daily driver. Also in the middle of sanding some surface rust on the middle of the door. The car is an 89 SC, manual trans. 3.8L V6. Thanks for the time and advice.

07-17-2007, 01:24 PM
This all sounds like good advice. I just don't understand that the tstat gauge never went passed the blue line and now when I changed the temp sensor last week now the temp is almost at the 'M' before the fan comes on and the 'Check Gauges' light is on until it goes down to the 'N'. And all of this in the passed week. Thanks for the time and advice.

07-17-2007, 02:28 PM
That sensor is iffy at best. I've seen the needle move alot just by turning on the headlights.

If the fan is not coming on until you have a gauge light, it sounds like there is a problem with the low speed fan not working, and your only getting the high speed. Either your IRCM module is shot or the low speed windings in your fan are shot.

If its possible, turn on your a/c. The low speed on your fan should come on while a/c is selected. If it doesn't then I suggest trying to find someone with a spare IRCM and swap it out and see if that fixes it.

07-18-2007, 11:15 AM
I've turned on the A/C on reg and max and the fan does not come on. I think we're on to something here. Can someone tell me what a IRCM is and located and also were and how to check or change the high and low speeds on the fan motor? 89 SC V6 3.8L Manual Trans.

07-18-2007, 11:29 AM
The IRCM is located right behind the PS head light next to the radiator.....

07-18-2007, 11:43 AM
If you search for IRCM wire 14 on here you will find that if you cut it, the fan will come on all the time. I did this on mine, but i spliced in a spade connector to swap back and forth from stock to normal. My IRCM Is shot however (burned up before the mod) so i always leave it on. Mine is not a daily driver though. I did daily drive mine for 2 years with the cut wire and it ran great and always stayed cool.


07-18-2007, 12:02 PM
Where on here do I fined wire 14 on the IRCM and if I cut it what would be the best way to turn it off on the colder days

07-18-2007, 01:59 PM
See this thread for the diagram.

You can see it clearly in the "Where is it located PDF"

The IRCM is behind the passenger headlight.
Remove the air cleaner and intake.
Unbolt the 3 bolts holding down the lower part of the air cleaner.
There will be a large bundle of wires going into a black box that is mounted to the radiator support with 1 smaller hex screw.

That black box is the IRCM. They are a well known problem on these cars. If you disconnect the box from the harness and look down into the connector you should see very small numbers (or at least a 1, indicating pin 1).
Find the corresponding wire and give yourself about 6 inches on either side (so you can reconnect it later if you want/need).

Once you cut the wire, reconnect the box. Turn your key to the first click (dont start), and you should hear the fan whiiiiiiiiiiiiiiiiiiiiiiiiiiiirrrrrrrrr up. Its pretty loud. You can switch off the ignition. I would wrap the ends with electrical tape to prevent accidental grounding (or use a protected spade connector pair like you can get at any auto parts store).

I should stress this isin't the ideal way to fix the problem. Replacing the IRCM would be ideal. But they can be hard to find in good condition and the car will run just fine this way. For me, I needed the car to get to work/school.

There is no real need to turn it off in the winter as your thermostat will close when the engine is too cold and recirculate the coolant in the block. I drove mine through 2 Minnesota/Michigan winters this way without trouble. Temp stayed right at normal.

If you want though, crimp the spade connector on there and plug it back in in the winter, but remember, you still wont have low speed fan if the IRCM Is hosed.


07-19-2007, 11:05 AM
The IRCM was easy to get to since I don't have the air box (cone filter down by pas fog light ). I cut the #14 wire and the fan stays on. So the problem must have been my IRCM since I have the fan on now right? I'm going to use my fog light switch to turn the fan on and off since my fog lights are damaged anyway and not ever planning on using them. Just one quick question, is there any danger to my fan or anything else in my IRCM by leaving that circuit open? Thanks Again.

07-19-2007, 08:45 PM
Not a good idea to use the fog switch for switching the cooling fan on & off. That switch will NOT handle the amps that the fan draws. Think about it, the fuseable link for the fan is rated something like 30 amps. The fogs have a 15 amp fuse. I really don't think you should do it, but it's your car.
Good luck.

07-19-2007, 09:19 PM
get you a high aperage relay before you go doing that... trust me.. you'll melt some wires bad.

07-20-2007, 01:23 PM
It was just an idea because I'm not using that switch anyway. But thanks very much, I might of over looked that. But if I get a different toggle switch and run a 30 amp fuse, should this work? I'll put the new switch were the fog light switch was just for convienence. Am I hurting something by leaving the fan on all the time with an open cicuit? And should I put the fuse before or after the switch? Thanks again.

07-27-2007, 12:59 PM
Can anyone give an answer for the above questions? I'm just cautious and don't want to damage anything. Thanks.

07-27-2007, 01:17 PM
get atleast a 30-40 amp relay... use some 12-10 ga wire for the battery to the fan, ground it to the chassis (theres a couple screws available on the core support) make sure you use a 30a inline fuse (for safety's sake) overkill is good in this situation... your fan should last a few years or so, hooked up like this... but definitely, get you a bigass relay and use that... tap the cig lighter 12v for the switch signal to the relay. also, if you wanted, you could throw a dial on the relay, and use it to control fan speed.

07-27-2007, 01:40 PM
The IRCMs job is to manage the fan, if its toast....its toast. You cant hurt it any more than it already is.

If you want to make your fan switchable, i would suggest getting a relay. You could easily pull one with a socket from a junk yard for cheap. I would suspect, using a switch to disconnect/connect wire 14 would be OK, I will look at the schematic tonight.

I would NOT run +12v----Switch-----Fan-----GND. This would be the makings of a good olde fashioned car fire.

The way you should do it:
| |
'-[swich]-o o
| |
3---- \ <<<<12v Automotive Relay
| |
GND----o o--------FAN--------GND

07-27-2007, 01:48 PM
lol. exactly.. if you really wanted it to be completely automatic... just tap the power wire going to your stereo for your relay. everytime you turned the car on, the 12v would hit the relay, and you wouldnt have to switch it on or off... aaand.. you could turn your key to the acc position to cool down your motor in the staging lanes if you were racing... win-win... just do it that way. i learned the hard way, by melting wires that i needed a relay for my foglights.:rolleyes:

07-27-2007, 01:48 PM
Perhaps use a www.dccontrol.com