Yes. I have actually "fixed" a loose/dirty connection just by unplugging a connector and then reconnecting it. Areas where they use salt or "brine" can cause havoc on things like that.
Rad Fans run with no key on cold engine
- Thread starter wifes_truck
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wifes_truck
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yes i agree salt and electrical stuff.... great combination... lol
The cover for the PCM (if this is what it is called on the truck), is covered pretty decent in a plastic enclosure. just in a bad place.... I didn't want to pull to ******* the main plug to dis-lodge the wires as room is tough to find where they located this thing. figured if its not broken, don't fix it theory kicked in. (looked way to clean) lol
cheers
The cover for the PCM (if this is what it is called on the truck), is covered pretty decent in a plastic enclosure. just in a bad place.... I didn't want to pull to ******* the main plug to dis-lodge the wires as room is tough to find where they located this thing. figured if its not broken, don't fix it theory kicked in. (looked way to clean) lol
cheers
wifes_truck
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Well, that was a short lived fix ... Last night she went to jump in and head into town for last minute store run...
Dead Battery ... only guess can be a parasitical on again off again fan problem ... why would a set of fans just turn themselves on for no reason?
On the relays it is fan 1 that controls this running. can anyone tell me if fan one is the one that is controlled by the A/C? we have no coolant charged in the A/C and do not use it. I am at the point of keeping this relay out of the relay box and having the truck just running with out for a while. that will eliminate the run/no run without a key or any power to the fans from relay #1.
I might need to pull the wire harness off the pmc and take an investigating look there, but, by looking at the condition of those wires I would probably be wasting my time.
Only other thing is maybe a mouse has chewed a ground wire somewhere... but then that on/off would run 100% of the time. As this problem is not 100% If the truck is turned on for 5 mins, and turned off no fans keep running. however just turn the key to on position off and back a few times, then pull key out of the ignition. Bamm fans turn on.
completely baffled on this one now.
cheers
Dead Battery ... only guess can be a parasitical on again off again fan problem ... why would a set of fans just turn themselves on for no reason?
On the relays it is fan 1 that controls this running. can anyone tell me if fan one is the one that is controlled by the A/C? we have no coolant charged in the A/C and do not use it. I am at the point of keeping this relay out of the relay box and having the truck just running with out for a while. that will eliminate the run/no run without a key or any power to the fans from relay #1.
I might need to pull the wire harness off the pmc and take an investigating look there, but, by looking at the condition of those wires I would probably be wasting my time.
Only other thing is maybe a mouse has chewed a ground wire somewhere... but then that on/off would run 100% of the time. As this problem is not 100% If the truck is turned on for 5 mins, and turned off no fans keep running. however just turn the key to on position off and back a few times, then pull key out of the ignition. Bamm fans turn on.
completely baffled on this one now.
cheers
You can just unplug the a/c compressor clutch and leave the relay or leave plugged in and cross the wires at the low pressure cut off switch and then unplug the relay to see if that shuts the fans off. If you turn the a/c on and the low pressure switch is crossed and the compressor is plugged in, that should turn on the fans and then unplug relay as you wish.
wifes_truck
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hi ron,
yes that is looking like what i will try tomorrow and see if it can be taken out like that. nothing is adding up for sure. Purchased a couple new relays just to see if that will make a difference. marked one of the old ones ( 2 same) with a black marker, and started unplugging the 4 pronged ones (2) and at first it stopped the fan for spinning... i was HEY maybe it is a relay.... so.... turned on the truck to see ... nope, fan went on after turning off the ignition...
will need to check into the deleting of the A/C stuff and seeing if I can bypass the sending unit for that fan.
cheers and cross fingers for tomorrow.
yes that is looking like what i will try tomorrow and see if it can be taken out like that. nothing is adding up for sure. Purchased a couple new relays just to see if that will make a difference. marked one of the old ones ( 2 same) with a black marker, and started unplugging the 4 pronged ones (2) and at first it stopped the fan for spinning... i was HEY maybe it is a relay.... so.... turned on the truck to see ... nope, fan went on after turning off the ignition...
will need to check into the deleting of the A/C stuff and seeing if I can bypass the sending unit for that fan.
cheers and cross fingers for tomorrow.
Good luck and let us know.
wifes_truck
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Well.... A friend came over today and said, "lets tackle this thing"
We retraced everything we could find that has a wire attached to it. took apart, tested, pushed, pulled, cussed and bled on, in, under or above this Tahoe.
For the life of us we could not find a sending unit beside the water pump, thermostat housing. Just doesn't seem to be there. The only sending unit we could find was above the #1 plug.
we disconnected all electrical for the A/C, and removed the relay and 10 amp fuse. cleaned all battery posts and checked all ground connections.
Everything we tested and tried was confirmed pointless by the test light we placed into the positive plug for the fan and grounded to batt. the light would just stay on, meaning we had not solved the fan on situation.
For a last attempt i said, well lets take out that wire connection for the PMC. this time we took it completely off the plug in. we looked it over, and as suspected, the whole thing looked spotless. no corrosion nor any sign that would make a person think a fault was there.
We replaced it all back up. re-hooked the battery and waited for the test light to come on .. and waited ... and waited ... AND WAITED ........
Nothing .... we looked at each other with that WTF expression ....
been 3 hours now, wife took the truck to town 2 hours ago and its been sitting for an hour now... still nothing .....
One thing is 100% for certain ... I am not holding my breath that it is fixed (been down that road) LOL If this shorts out again I will take out the #1 fan relay and I have a Flex-Lite probe and relay system new in package on the wall in the shop that i was saving for a project (but the fan I bought for it came with its own controller. so i will just bypass the Tahoe relay system and build my own fan controlling system.
this is to much work and effort...
cheers and fingers crossed.
We retraced everything we could find that has a wire attached to it. took apart, tested, pushed, pulled, cussed and bled on, in, under or above this Tahoe.
For the life of us we could not find a sending unit beside the water pump, thermostat housing. Just doesn't seem to be there. The only sending unit we could find was above the #1 plug.
we disconnected all electrical for the A/C, and removed the relay and 10 amp fuse. cleaned all battery posts and checked all ground connections.
Everything we tested and tried was confirmed pointless by the test light we placed into the positive plug for the fan and grounded to batt. the light would just stay on, meaning we had not solved the fan on situation.
For a last attempt i said, well lets take out that wire connection for the PMC. this time we took it completely off the plug in. we looked it over, and as suspected, the whole thing looked spotless. no corrosion nor any sign that would make a person think a fault was there.
We replaced it all back up. re-hooked the battery and waited for the test light to come on .. and waited ... and waited ... AND WAITED ........
Nothing .... we looked at each other with that WTF expression ....
been 3 hours now, wife took the truck to town 2 hours ago and its been sitting for an hour now... still nothing .....
One thing is 100% for certain ... I am not holding my breath that it is fixed (been down that road) LOL If this shorts out again I will take out the #1 fan relay and I have a Flex-Lite probe and relay system new in package on the wall in the shop that i was saving for a project (but the fan I bought for it came with its own controller. so i will just bypass the Tahoe relay system and build my own fan controlling system.
this is to much work and effort...
cheers and fingers crossed.
Ever since you said that you wiggled wires down there and it stopped for a while till it came back on, I had said to really get in there and unplug it and inspect it and see what you could see, see post #17...................................................................but noooooooooooooooooooooooooooo, you would not take that chance and I understand why but myself, I have always wanted to get to the bottom of things. Even if what you did does not fix it, it has something to do with that circuit on that wire. Intermittent electrical problems are the worst there is and can make you lose your mind. My best time with these is when someone else, YOU, are doing it. I sometimes do not have the patience for sure. I do hope it is fixed, I really do. If the problem comes back, I feel for ya. I do. But if it doesn't come back, well I will rub it in a little bit. Well, maybe more than a little bit. Who am I kiddin'. I will rub it in a LOT!
wifes_truck
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well it was short lived. took the dog out for a squirt.... guess what... the fans were running so I am at a complete loss why. How is it possible a truck that is just sitting there can start up on its own for no reason? Won't be happening again tonight, unplugged the fans .... So much for was it the PCM? truck sat 4 hours, and i was out there an hour ago to check it. and just now it is running.... i give up.
cheers any options besides a KEG TNT?
cheers any options besides a KEG TNT?
Well, hell, my gloating ends........damn it. On this year, does anyone know if there is a separate coolant temp sensor and a separate sender for the gauge, like it used to be? Or am I just old enough and out of the shops long enough that it has all changed enough where I am out of the loop? I feel for ya, I do.
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