3.1 fan issue
Thread Starter
Member
Joined: Jul 2002
Posts: 312
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From: Manassas , V.A
Car: 92 Formula
Engine: 5.0L TBI
Transmission: 700R4
Axle/Gears: 3.73 posi
3.1 fan issue
90 firebird 3.1
The fan will not kick on when the a/c goes on or when temp exceeds 230.
List of replacements:
Fan Switch
Fan Relay
Ecm
the fan motor works because i have jumped the relay and it cut on. the relay has one hot when ign is off and two when it is on. The fan will always cut on in diagnostic mode or when i unplug the fan switch. It just won't work with normal driving when ac is turned on or when the temp hits 230
What else is there to replace? Any ideas?
The fan will not kick on when the a/c goes on or when temp exceeds 230.
List of replacements:
Fan Switch
Fan Relay
Ecm
the fan motor works because i have jumped the relay and it cut on. the relay has one hot when ign is off and two when it is on. The fan will always cut on in diagnostic mode or when i unplug the fan switch. It just won't work with normal driving when ac is turned on or when the temp hits 230
What else is there to replace? Any ideas?
Member
Joined: May 2003
Posts: 242
Likes: 0
I could be mistaken, but doesnt the fan have its own coolant temp. sensor? Might be the problem.
Sounds like your fan functions normally, but just has no idea when to come on.
Lemme see what Haynes says. Not at school so I cant get on AllData
Sounds like your fan functions normally, but just has no idea when to come on.
Lemme see what Haynes says. Not at school so I cant get on AllData
Senior Member
Joined: Jul 2001
Posts: 904
Likes: 1
From: Modesto, CA USA
Not to sure how to diagnose what is going on, but here's what happened to mine when I was having the same prob.
I had 2 problems.
1.) Low A/C charge. discharged and recharged with R134a conversion kit. Over charge by mistake and blew A/C compresor. Replaced and paid closer attention. It all works again.
2.) Bad temp gauge. Thought my temp was getting to 260*, but in reality it was kicking at the normal time. Replace with it with aftermarket mechanical gauge, and all is good again.
I prefered the mechanical gauge over the electrical gauge due to a faster and more accurate respones. Electrical gauges are not as accurate as they have a given OHM resitance for a degree range. For example, say the sensor is reading 12 OHM it would mean that the temp was between 205* and 208*. So the gauge would read 208* when it could actually be 205*.
Well enough rambling from me.
I had 2 problems.
1.) Low A/C charge. discharged and recharged with R134a conversion kit. Over charge by mistake and blew A/C compresor. Replaced and paid closer attention. It all works again.
2.) Bad temp gauge. Thought my temp was getting to 260*, but in reality it was kicking at the normal time. Replace with it with aftermarket mechanical gauge, and all is good again.
I prefered the mechanical gauge over the electrical gauge due to a faster and more accurate respones. Electrical gauges are not as accurate as they have a given OHM resitance for a degree range. For example, say the sensor is reading 12 OHM it would mean that the temp was between 205* and 208*. So the gauge would read 208* when it could actually be 205*.
Well enough rambling from me.
Thread Starter
Member
Joined: Jul 2002
Posts: 312
Likes: 0
From: Manassas , V.A
Car: 92 Formula
Engine: 5.0L TBI
Transmission: 700R4
Axle/Gears: 3.73 posi
the ac blows cold as can be when the fan is jumped. It was converted to 134 last summer.
What i did notice deals with the fan switch on the ac line. If I unplug that switch the fan does not come on. I was reading through post and it says if u unplug it, it is supposed to come on. So then i tryed to ground it out and still nothing. This may be normal but i don't know.
As for the guage, i don't think that is the problem because i could let the motor run to 260 and it would still not cut on. + it should still cut on anyway when i turn the ac on.
Thanx for the replies. Any other ideas?
What i did notice deals with the fan switch on the ac line. If I unplug that switch the fan does not come on. I was reading through post and it says if u unplug it, it is supposed to come on. So then i tryed to ground it out and still nothing. This may be normal but i don't know.
As for the guage, i don't think that is the problem because i could let the motor run to 260 and it would still not cut on. + it should still cut on anyway when i turn the ac on.
Thanx for the replies. Any other ideas?
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