Fan bypass
#1
Fan bypass
Hi everybody,
My cooling fan is not working.
About 6 months ago I replaced the fan switch, the Coolant temperature sensor and the relay. Oh and the ecm is about 6 months old.
I really just want them to work. Frankly trouble shooting is not my strong suit and I have a lot of things I need to do. Repair a universal, study for my exams go to work both jobs.
I did this once before and ran power to my 1984 fans. But if I am understanding things correctly. All I need to do is run a ground wire, correct.
Presently
The ECM fuse is good
when the car gets over 205 fan operating temperature when everything is operating correctly
The fan does not come on. So that means the car is not trying to start the fan.
So I am thinking that if I put a wire on the correct wire in the relay the fan should come on.
What pins on the relay do I need to ground to operate the fan.
Thank you
Joe
Corvette the car you love to hate
My cooling fan is not working.
About 6 months ago I replaced the fan switch, the Coolant temperature sensor and the relay. Oh and the ecm is about 6 months old.
I really just want them to work. Frankly trouble shooting is not my strong suit and I have a lot of things I need to do. Repair a universal, study for my exams go to work both jobs.
I did this once before and ran power to my 1984 fans. But if I am understanding things correctly. All I need to do is run a ground wire, correct.
Presently
The ECM fuse is good
when the car gets over 205 fan operating temperature when everything is operating correctly
The fan does not come on. So that means the car is not trying to start the fan.
So I am thinking that if I put a wire on the correct wire in the relay the fan should come on.
What pins on the relay do I need to ground to operate the fan.
Thank you
Joe
Corvette the car you love to hate
#2
Le Mans Master
Hi everybody,
My cooling fan is not working.
About 6 months ago I replaced the fan switch, the Coolant temperature sensor and the relay. Oh and the ecm is about 6 months old.
I really just want them to work. Frankly trouble shooting is not my strong suit and I have a lot of things I need to do. Repair a universal, study for my exams go to work both jobs.
I did this once before and ran power to my 1984 fans. But if I am understanding things correctly. All I need to do is run a ground wire, correct.
Presently
The ECM fuse is good
when the car gets over 205 fan operating temperature when everything is operating correctly
The fan does not come on. So that means the car is not trying to start the fan.
So I am thinking that if I put a wire on the correct wire in the relay the fan should come on.
What pins on the relay do I need to ground to operate the fan.
Thank you
Joe
Corvette the car you love to hate
My cooling fan is not working.
About 6 months ago I replaced the fan switch, the Coolant temperature sensor and the relay. Oh and the ecm is about 6 months old.
I really just want them to work. Frankly trouble shooting is not my strong suit and I have a lot of things I need to do. Repair a universal, study for my exams go to work both jobs.
I did this once before and ran power to my 1984 fans. But if I am understanding things correctly. All I need to do is run a ground wire, correct.
Presently
The ECM fuse is good
when the car gets over 205 fan operating temperature when everything is operating correctly
The fan does not come on. So that means the car is not trying to start the fan.
So I am thinking that if I put a wire on the correct wire in the relay the fan should come on.
What pins on the relay do I need to ground to operate the fan.
Thank you
Joe
Corvette the car you love to hate
Last edited by Cruisinfanatic; 04-29-2017 at 06:40 PM.
#3
The stock TCS is set for 228. My PROM and sensor worked at 205. Besides the car went to 235 this afternoon and no fan.
Thank you
Where is the Fan Relay? I forgot and my manual is fn useless.
My FSM for the 1984 had a decision tree. Check relay pin A etc... Is there one for the 1989. I have paged through almost every page in this book and I cannot find it.
Thanks again
Thank you
Where is the Fan Relay? I forgot and my manual is fn useless.
My FSM for the 1984 had a decision tree. Check relay pin A etc... Is there one for the 1989. I have paged through almost every page in this book and I cannot find it.
Thanks again
#4
The stock TCS is set for 228. My PROM and sensor worked at 205. Besides the car went to 235 this afternoon and no fan.
Thank you
Where is the Fan Relay? I forgot and my manual is fn useless.
My FSM for the 1984 had a decision tree. Check relay pin A etc... Is there one for the 1989. I have paged through almost every page in this book and I cannot find it.
Thanks again
Thank you
Where is the Fan Relay? I forgot and my manual is fn useless.
My FSM for the 1984 had a decision tree. Check relay pin A etc... Is there one for the 1989. I have paged through almost every page in this book and I cannot find it.
Thanks again
Last edited by WVZR-1; 04-29-2017 at 07:03 PM.
#5
If you have the FSM the diagnostics follow directly the wiring diagram. For your '89 try 8A-31-0 for diagram and pages that follow for diagnostics. There's other sections that ultimately could be involved such as 6E if you have a SES/CEL but to accomplish what you mention 8A-31-0
Thank you so much.
I did fix it. I remembered that the fan relay is on the radiator. I turned on the key and there is no power at the relay. So, I ran power to the relay. Let the car heat up and at 206 degrees f. We have fan operation, HOORAH!!!
I do not know why there was no power but, it is working correctly.
On my 1984 I ran power to the fan. Eventually the switch I used melted. At least now the system is operating as it would normally.
Thank you all for the help.
And thank you for the diagram pages. This book drives me nuts.
Good night and thanks again
#6
Burning Brakes
fuseble link
#7
you are correct, Sir!
A couple of months ago the car just stopped running. My mechanic said that seven of the eleven fusible links were nfg. He replaced them with a fuse block that contains five fuses. So this morning when I was aout to establish the hot to the relay I looked at the fuses. One of the fuses was blown. Turns out it is the fuse that supplies power to the fan relay. I changed the fuse and TADA. I had power going to the relay. I ran the car and the fan came on at 205 degrees F.
Thank you all.
I did my axle universals ALL DAY. how long is that job supposed to take. Just wondering.
A couple of months ago the car just stopped running. My mechanic said that seven of the eleven fusible links were nfg. He replaced them with a fuse block that contains five fuses. So this morning when I was aout to establish the hot to the relay I looked at the fuses. One of the fuses was blown. Turns out it is the fuse that supplies power to the fan relay. I changed the fuse and TADA. I had power going to the relay. I ran the car and the fan came on at 205 degrees F.
Thank you all.
I did my axle universals ALL DAY. how long is that job supposed to take. Just wondering.
#8
Great thread....
So today My Lingenfelter 630 coolant temperature got up to 240 in some stop and go traffic. I quickly jumped on the highway and it cooled right down to 210 which is what I think is pretty normal for my car. The air-conditioning is not working now either. After quickly looking I can tell the fan is running when the car is just over 200 but seems to be running at a low percentage. Clicking the air conditioning on does not change the fan speed but I do see the clutch engaging. From reading this thread I am thinking it's possibly the module?
So today My Lingenfelter 630 coolant temperature got up to 240 in some stop and go traffic. I quickly jumped on the highway and it cooled right down to 210 which is what I think is pretty normal for my car. The air-conditioning is not working now either. After quickly looking I can tell the fan is running when the car is just over 200 but seems to be running at a low percentage. Clicking the air conditioning on does not change the fan speed but I do see the clutch engaging. From reading this thread I am thinking it's possibly the module?
#9
My '93 has an issue with the quad-driver module, or at least that 's that code that was (is still) being tossed. IIRC, I had a mechanic replace the sensor with a mechanical one that switches the fan on at temp. (Again, IIRC), it's a standard enough fix that there's a kit (from GM?) The code's still there but the fan goes on as necessary. Having said that, if I had it to do again, I'd try and run down the problem, perhaps starting with replacing the QDM.
Best,
Jerry
Best,
Jerry
Last edited by gdgeorge; 03-31-2020 at 07:42 PM.
#10
Melting Slicks
Not trying to threadjack.
#11
Safety Car
Hello Jseremba!
If you are going to wire in a fan be sure to use a relay to handle the current. I have a VW Vanagon and it had the power going thru the headlight switch which burned out switches quickly! I bought a 30 amp relay and wired it in so the switch only "energizes" the relay and does not power the headlights. The power flows from the battery Positive to the headlights directly thru the relay and works much better than what VW left in the Car. My headlights are much brighter now without voltage drops getting to the headlights. I would make a new circuit to supply power to the fans using a 30 or40 amp relay. It is easy to do as well.. If you need help just ask and someone will show you how easy it is to use a relay. I keep several on hand in my garage as I find applications regularly.
My cooling fans on my C3 are a pair of SPAL 11" fans in a shroud. The control system is the Derale #16795 PWM Electronic Fan Controller. My fans start wherever the controller senses heat and start at 50% power and ramp up as need to hold the heat down. The noise reduction is incredible... as the fans only run at 100% when they absolutely have to. This is the smartest fan controller I have seen so far.
What year Corvette had 11 fusible links in it? My 1988 C4 has only Seven Fusible links at the post behind the battery under the side panel. They are indeed important and were designed to blow more slowly than a fuse would normally. When I work on parts like these I use what Chevrolet used. It is your last line of defense in case of any shorts pre-fuse block.
Be well, Stay Well!
I could never "Hate a Corvette", they do frustrate us every now and then but Hate? I don't think so...
If you are going to wire in a fan be sure to use a relay to handle the current. I have a VW Vanagon and it had the power going thru the headlight switch which burned out switches quickly! I bought a 30 amp relay and wired it in so the switch only "energizes" the relay and does not power the headlights. The power flows from the battery Positive to the headlights directly thru the relay and works much better than what VW left in the Car. My headlights are much brighter now without voltage drops getting to the headlights. I would make a new circuit to supply power to the fans using a 30 or40 amp relay. It is easy to do as well.. If you need help just ask and someone will show you how easy it is to use a relay. I keep several on hand in my garage as I find applications regularly.
My cooling fans on my C3 are a pair of SPAL 11" fans in a shroud. The control system is the Derale #16795 PWM Electronic Fan Controller. My fans start wherever the controller senses heat and start at 50% power and ramp up as need to hold the heat down. The noise reduction is incredible... as the fans only run at 100% when they absolutely have to. This is the smartest fan controller I have seen so far.
What year Corvette had 11 fusible links in it? My 1988 C4 has only Seven Fusible links at the post behind the battery under the side panel. They are indeed important and were designed to blow more slowly than a fuse would normally. When I work on parts like these I use what Chevrolet used. It is your last line of defense in case of any shorts pre-fuse block.
Be well, Stay Well!
I could never "Hate a Corvette", they do frustrate us every now and then but Hate? I don't think so...
Last edited by ctmccloskey; 04-02-2020 at 03:50 PM.
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