Help! Cooling fans run continuously.

[Rabbit]

1995 C-4, 31K. Cooling fans are running continuously. A/C is off, engine running at 197*. Checked for codes, none.

Any suggestions? Thank you,

 

[hcbph]

Is this new or something that's been going on all along?

Do they turn on as soon as the key is turned on? PO may have hardwired them to run all the time. Could also have frozen relays. Could have a switch that was wired in that's on.

 

[forrest]

Is this new or something that's been going on all along?

Do they turn on as soon as the key is turned on? PO may have hardwired them to run all the time. Could also have frozen relays. Could have a switch that was wired in that's on.

I agree some of the relays could be stuck or hot wired, but also you may have a faulty A/C switch see if when you unplug some of the A/C switches if the fans will shut off. if they do let the car run but monitor the Coolant and see if the fans will kick on at there proper temp. But definitely give a good look for fan system being altered, or stuck relays.

 

[Rabbit]

Nothing has been changed regarding the fans, all original. The fans start a couple of minutes after the engine is started. Guess I'll start with the relays & go from there. Everything else appears to be normal. This started a few days ago????? Will check the a/c.

Thanks for the replies.

 

[GWinter]

If the air is on both fans should run. Turn the air of if it is on. Wasn't a switch added by previous owner that you turned it on unknowingly ?

 

[Rabbit]

If the air is on both fans should run. Turn the air of if it is on. Wasn't a switch added by previous owner that you turned it on unknowingly ?

No matter the switch positions the fans continue to run.


Thanks,

 

[GWinter]

If I remember right the fans run when you jumper the OBD port to get codes, you didn't by chance leave a jumper on ? Maybe not applicable to OBDII which started showing up in 95

 

[Rabbit]

If I remember right the fans run when you jumper the OBD port to get codes, you didn't by chance leave a jumper on ? Maybe not applicable to OBDII which started showing up in 95[/QUOTE


]The DLC is clear. Tks!

 

[Hib Halverson]

First, if any code is set or the ECM is in field service mode (serial line grounded with the engine running), the fans will run continuously.

2) the question was asked earlier if the MIL is coming on during bulb check. Is it?

3) if the fans come on after the engine is running, the relays are not "stuck" or "hot wired". My guess is the engine starts and runs for a few minutes but, as soon as the ECM detects a fault, the fans come on.

4) if the MIL is not on at bulb check, you need a scan tester to read codes.

 

[Rabbit]

First, if any code is set or the ECM is in field service mode (serial line grounded with the engine running), the fans will run continuously.

2) the question was asked earlier if the MIL is coming on during bulb check. Is it?

3) if the fans come on after the engine is running, the relays are not "stuck" or "hot wired". My guess is the engine starts and runs for a few minutes but, as soon as the ECM detects a fault, the fans come on.

4) if the MIL is not on at bulb check, you need a scan tester to read codes.

Will check your instructions this afternoon.


Tks,

 

[Rabbit]

Will check your instructions this afternoon.


Tks,

Ses bulb check is OK. Ran diagnostics using on board computer. No codes.

Am going to take it to dealer tomorrow.

Want to thank all who responded your interest is appreciated.

 

[Rabbit]

Ses bulb check is OK. Ran diagnostics using on board computer. No codes.

Am going to take it to dealer tomorrow.

Want to thank all who responded your interest is appreciated.

Problem was...a/c high pressure sensor skewed. Also had system recharged.