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Discussion Starter · #1 ·
Both cooling fans on my 95 Impala are always on !? I have changed the temp switch on the left side of the block, the coolant temp switch on the front of the water pump, switched fan relay's, installed new water pump and thermostat, and they still both stay on !?!?! Its really driving me up the wall !!!
 

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Is your check engine light on? The fans will run full-time then.

Does you check engine light come on for the bulb test at startup or when the key is on, engine off? If the bulb is missing or burned out, then the PCM runs in open loop all the time, and runs the fans full time.
 

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Discussion Starter · #3 ·
Is your check engine light on? The fans will run full-time then.

Does you check engine light come on for the bulb test at startup or when the key is on, engine off? If the bulb is missing or burned out, then the PCM runs in open loop all the time, and runs the fans full time.
As a matter of fact, I don't ever see my CEL on at key up ? I'm suspecting a burned bulb or something ? If the CEL should say "Service Engine Soon", then I have definitely never seen it. I will take the cluster apart and troubleshoot. Thanks !
 

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Sounds like your issue is solved. I had the very same thing when I bought my '95 9C1. Someone had removed the check engine bulb, probably a quick and dirty 'fix' back in its in-service days with the Arkansas State Police.

On these cars, the CEL is an outline of an engine with 'CHECK' underneath.

Bulbs are accessible at the back of the cluster, all you have to do is remove it, then you can R&R bulbs. If you know what you're doing, its a 20 minute job.
 

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Discussion Starter · #5 ·
OK, so I removed the cluster and noticed that the bulb is burned out . I removed the CEL bulb and replaced it with the working windshield fluid low bulb, put it back together and STILL NOT WORKING ??? Checked fuses (pulled each one out) all OK, when I checked either prom (2 outer tabs the bulb resides in) with my test light, the bulb goes on but dim ?? WHY IS MY CHECK ENGINE LIGHT NOT WORKING ???
 

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Forget the light.. Check the OBD port and see if you have a code.. Fix the light later if in fact you have a code that is coming on..
 

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Discussion Starter · #7 ·
Forget the light.. Check the OBD port and see if you have a code.. Fix the light later if in fact you have a code that is coming on..
It is an OBD 1 , how do I retrieve the codes ?
 

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Discussion Starter · #8 ·
Help ?!
 

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You will need someone to scan the OBDI port for errors . . You may be able to go to Autozone and have them scan it for errors. If not see if someone has a scanner to read the errors. Just make sure the scanner is able to read OBDI codes...
 

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both cooling fans on? are you using the A/C? if so both will always run
 

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Discussion Starter · #11 ·
both cooling fans on? are you using the A/C? if so both will always run
A/C is off and not an issue. It is something to do with the CEL, computer is in open loop mode,l have to find out why my CEL is not working, already changed the bulb btw .
 

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both cooling fans on? are you using the A/C? if so both will always run
Wrong. The passenger side primary fan runs with the A/C. The other one should not be on. Something is wrong and that is why they are both on. Pull the code(s) and find out what is really going on.
 

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Discussion Starter · #13 ·
Wrong. The passenger side primary fan runs with the A/C. The other one should not be on. Something is wrong and that is why they are both on. Pull the code(s) and find out what is really going on.
I asked before and didn't get an answer ? How do I pull the code ? I have an OBD 1. And Autozone NO LONGER does this .
 

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Get an ALDL cable from pcmperformance.com or one of the other vendors here, download Freescan or Datamaster and see what is going on.
 

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Discussion Starter · #15 ·
Get an ALDL cable from pcmperformance.com or one of the other vendors here, download Freescan or Datamaster and see what is going on.
As well as a laptop I assume ?? By the time I order and receive all said items (around $500), I could probably pay mechanic or dealership around $50 . Thanx for the option though. Just thought there was an easier way.
 

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Discussion Starter · #16 ·
UPDATE ....
I went to Pep Boys and they ran any codes that I might have and I only have one and it is for the CEL not working, LOL ! So I went home, took my cluster apart, again, and made sure the new bulb I put in for the CEL was still good, and it is, but still will not light up! So this time, I took the whole thing apart, re-soldered a few worn spots on the back, and the I noticed, location J14 was disconnected !! I tried to re-solder that point but didnt turn out to good. Does anyone know what function J14 operates ? Its behind the voltage and temp gauges.
 

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As well as a laptop I assume ?? By the time I order and receive all said items (around $500), I could probably pay mechanic or dealership around $50 . Thanx for the option though. Just thought there was an easier way.
There are good OBDI scanners available if you don't want the cable and laptop (got a friend? - any old laptop will do) route. Try AutoXray or others .....$ 150 will get a great one.
 

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Discussion Starter · #18 ·
There are good OBDI scanners available if you don't want the cable and laptop (got a friend? - any old laptop will do) route. Try AutoXray or others .....$ 150 will get a great one.
Thanx for the info, but as stated above, I already got it scanned, for FREE at Pep Boys. No serious codes, just a CEL light code saying its not working, trying to figure it out .
 

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Discussion Starter · #19 ·
Anyone know what J14 on the cluster board is for ? Is it related to the CEL ??
 

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Discussion Starter · #20 ·
Another update ... FINAL ! I used my test light to the brown / white wire which controls the CEL behind the instrument cluster at the pin connector and found no power when keyed on. I then followed the schematics to trace the wire to the ECM. I found the problem there !! Somebody (previous owner), stabbed into the wire leaving the hole exposed, causing it to disintegrate, so I soldered and covered the wire, test, and the CEL now works and fans go on only when they are supposed to !:)
 

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