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Short story first... Battery dead, hooked up charger for a whilie, tried to start... click click click. Not enough charge. Then fans came on. Open hood and charged somemore. Finally got her started, closed hood and drove for a while to help charge up the battery and strech her legs a bit.
Engine off, key out, fans still on. Open hood to trigger kill switch. What system tells the fans to keep running after engine is off till the bay area cools. I'm hoping it's one of the temp sensors. Not sure which one or if I messed up the fan controllers.
What should I check first.?
It's been at least 5 years since I don't anything under the hood besides changing the oil. I replaced all the underhood sensors prior to murphing it, but have since forgot which ones did what.
The aftermarket Murph Muffins are still controlled by the origianll controller via a Hans installed relay to protect exessive current draw and runs full blast as soon as any signal is sensed. Taking out the ramping up effect.
I may have just answered my own question. Need to make a beer run and pay Hans a visit.
But if it were a sensor, which one should I unplug to test?
As I am aware the trigger for the fan run on is the switch on top of the inlet manifold. If the hood is opened the bonnet [hood] switch near the 14 pin connector should stop the fans running for safety reasons- if the fans run on with the bonnet open then the bonnet switch is likely caput or so I would think. Mine fell to pieces recently so I simply disconnected it as I have no use for the lamp unit on the underside of the bonnet.
Disconnect this one first.
If the fans stop, the problem is this switch.
If it does nothing, look at the one on the transmission (auto). No pic of that one, sorry.
Thanks, intake manifold temp sensor is the one I need to check first. That seems to ring a bell. Presume it has a negative temp coeiffienct where thermistic resistance increases as temperature decreases?
I'm going to check to see if disconnecting stops the run on like open the hood does now.
Had zero awareness regarding a torque converter temp sensor. Seems odd to run fans up front to cool something oout back and nothing is pumping.
This is for a 1987 Auto. Not sure what happened to my signature and I'm not finding a place to edit it.
Had zero awareness regarding a torque converter temp sensor. Seems odd to run fans up front to cool something oout back and nothing is pumping.
This is for a 1987 Auto. Not sure what happened to my signature and I'm not finding a place to edit it.
Thats just it, a shorted circuit or a bad sesnsor back there will still trigger the fans..it doesnt know/care if the car is running or not. Its part of the same "Is something too hot" decision tree.
Fan amps (finned black device near the hood latch) are cranky and I'm told will most likely fail over time. My functioning unit was rebuilt to ensure I wouldn't get stuck when it failed. Of course the rebuild came in DOA, and had the exact symptoms you saw. The vendor did the right thing and replaced the bad one free.
I don't know how to check if it's working properly though. Maybe one of the gurus can chime in.
If you have a complete fan failure, all you have to do is drive like Kurt in the Carolinas.....That should provide adequate "passive" airflow for cooling. Ask me how I know......
Thats just it, a shorted circuit or a bad sesnsor back there will still trigger the fans..it doesnt know/care if the car is running or not. Its part of the same "Is something too hot" decision tree.
Not sure if Kurt's has the trans cooler mounted.....that would explain the fans coming on from that sensor....
[polite reminder to add that info to your signature section. Look under UserCP>signature]
Originally Posted by auzivision
This is for a 1987 Auto. Not sure what happened to my signature and I'm not finding a place to edit it.
You are an unpaid "User". Same as me. No sigline privileges.
Get into the habit of including that info in any post where you are asking for help (silly & offhand comments don't require it, but you can include it if you so desire).
Charged her up this weekend and blew off some dust this morning on the way to work today.
Fans remain on even after disconnecting the intake temp sensor.
IIRC, my setup uses the fan amps as a 'signal' that trips an aftermarket relay that feeds all 5 fans at once. So it's either the relay or the TC temp sensor.
Approximately where is the tranny temp sensor located? Guessing, maybe passenger side radiator end tank?
Hard to believe it's been this long since I've looked into this thing. I finally went out and replaced the battery last weekend (only cost $5.00 at Costco). Come to find out, my almost new battery was not holding a charge properly and all this time I thought the fans were killing it.
I'm back on the streets today. LOL, Little bumpy at first... flat-spotted the tires. License plates are up for renewal and I haven't even gone through a tank of gas since last year's renewal.
This car is going somewhere out of state this year. Seriously considering the Badlands if I can find a sidekick to share some of the driving.
02-19-2019, 04:17 PM
Cooling Fans keep on running
