The overheat continues..fan help please !!

notagt

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I have been fighting an overheat issue for 2 + years when car is driving down the highway. FINALLY tracked it to a kinked lower rad hose. Fixed and burped. Took one test ride for 20 miles..did perfect, stayed between 179 and 181. I went out today, again car did great, traffic, no issue, stopped for 20 minutes, car stayed at 176 ( as a note, as part of my chasing issue, lo speed on at 176, high at 182), even dipping to 174 where fan turned off. Out of nowhere, temp started climbing, hit 230 and I shut it down. I noticed with handheld sct redownloaded tune and fan came on, but cranked car, fan would start to turn and stop. Once car cooled down good, started and low fan came on as it should. Turned on AC and fan went to high speed and temp stayed at 179 to 181. After about 15 to 20 minutes with car running and AC on, fan suddenly stopped and never came back on, finally at 203 and climbing, I just shut her down. So it seems once car cool, fan will work correctly in lo/hi, but after a bit of time just shuts off and fan motor seems hot but hard to tell. Do you guys think I need a whole new fan or maybe a new resistor? Sorry for length of post, wanted it to be precise of what's going on. Thanks.
 

DSG2003Mach1

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personally once the fan quit I would jump out with a volt meter and verify proper voltage to the fan connector (or at least a test light and verify it's getting power). Then chase the resistor vs fan motor

I know the resistor is what gives it a low speed but not sure what happens if that fails - does it not run or does it default to high

@hotcobra03
 

hotcobra03

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Something I found on mine after yanking stuff

the fan connector. the fan side.

Has barrels. These on mine were back to far causing to go on and off
 

notagt

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So the one female connector on the fan itself is what ypur talking about? I don't think it's that, for 3 months now in garage fan has been working perfect, it seems once it's running for 20 minutes here in the garage, it will just shut off and won't work again till car is cool...screw it with all other stuff that is new, I just emptied and removed resvoir ( hoping that will avoid major reburp ),and removed IC tank, gonna get a new fan, ( think I put this one in 2017),any recommendations on where to get a GOOD stock replacement, mine says made in Thailand.
 

hotcobra03

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Yes that plug
And yes it is effect because it gets hot and cold
Barrels not fully over pins

as wires get hot when working it expands and stops power

Testing here is also easy
Run jumpers out of connector.

when fan stops see if wires are still powered

our site has a manual for you to use if you want to really fix it
 

DSG2003Mach1

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I don’t think there’s an actual OEM replacement anymore. I think doorman is the best you can do
 

notagt

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Yes that plug
And yes it is effect because it gets hot and cold
Barrels not fully over pins

as wires get hot when working it expands and stops power

Testing here is also easy
Run jumpers out of connector.

when fan stops see if wires are still powered

our site has a manual for you to use if you want to really fix it

Thanks, I will check that plug, would think if just got rid of plug period and hardwired would cure that problem.
 

SVTdreamin04

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All good stuff here. I found the resistor broke off on my fan which caused the low speed not to work and also had issues with the plug as well. Even though it’s a Cobra, still pretty much the same setup.


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notagt

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The saga continues and I am LOST, along with friends. O Old fan, I could remove 30 A fuse for low speed and with my tune, high speed came on. Since on my test ride , after about 50 miles fan stop working totally. I put in a new fan..now, at 140 degrees, I turned on AC and fan came on and shut off ac it stopped. As car kept runjing, I hit 182 ( hi speed in tune), nothing happenned, no fan. Temp hit 210, shut it off. Took my handheld and downloaded a constant fan on tune I have, fan came on while downloading tune, got done, cranked car...nothing, car got to 205 before I shut off, fan never came on. I then put original tune back in , again, while downloading, fan was running. I bought a new fan and now it's WORSE, this is fan #3 so I know my luck bad, but dang! ! So with old fan, car hit 172, low came on and car never ran hot in driveway, disconnect 30 A fuse, car hit hi speed temp and fan came on. Went for ride, temps perfect for first 30 miles, then fan stopped completely. Put in NEW fan, pulled 30 A fuse, hit 181, nothing, constant fan on tune, nothing, car at 195 put fuse back in ( the one on passenger side), nothing, AC on , nothing, but download a tune comes on. Could the CCRM be intermittent somehow? Other than the 30 A fuse on passenger wheel under hood, is there any relays somewhere I can check? Seems once car cools down completely, fan works fine in low and high, but now it's just no rhyme or reason when it will work or when it wont. This overheat crap going on 3 years and can't enjoy the car at ALL since never know when it will decide to act up. Has anyone gone aftermarket bypassing entire car electrical system with aftermarket fan with standalone type temp control for fan off on and what brand, type, etc. Sorry so long, just so done with this.
 

notagt

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Now worked perfect for an hour after I went back out to garage...low speed on at 176, off at 170 for 5 cycles, fan off at 170 and temp dropped to 168, at 168 with no fan on, turned on AC, fan came on high, left it running, temp dropped to 162, I shut off AC, fan stopped, once temp climbed to 174, low speed came on again till temp of 170, so for an hour worked EXACTLY like supposed to...WTF? Test ride tomorrow. Thanks for listening man
 

notagt

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All good stuff here. I found the resistor broke off on my fan which caused the low speed not to work and also had issues with the plug as well. Even though it’s a Cobra, still pretty much the same setup.

All I can think then is to cut male and female connector and just hardwire and solder.


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notagt

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Has anyone ever disconnected the 3 prong plug and somehow wired in one of those temp probe controllers to bypass entire system and have turn on with that probe that sticks on the radiator itself? I had a parts house one on my 79 F100 and it was perfect and easy. Figured if I knew how to wire one of those in the cars 3 prong plug ( which pin does what in the connector ?) I could at least then use to take pcm and everything else COMPLETELY out of the equation to see how fan runs with temp/radiator probe, high speed only would be fine I guess
 

ashleyroachclip

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I would wonder why the car gets hot going down the road , where you have the most air over the radiator .
In most , but not all cases, there is no need for a fan assist , while maintaining hiway speeds .
 

notagt

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Ok, I drove car today about 40 miles, highway and in town. It did perfect, highest temp I saw was at a stoplight hit 179, cruising temp would come down, at one point stayed around 172 at 70 mph. I did a good 2nd and 3rd gear pull to 28 psi, car hit 185 degrees, but back to 70 mph temp dropped steady to 172. I live out in the country, so on hard road did small burnout with line lock, then rowed thru the gears. Temp started climbing and by the time I got home (2 miles), temp hit 230, got out of car and fan wasn't running. What would make fan, after keeping car no higher than 181 degrees, just out of nowhere stop working just cause I got on the throttle good one time? Low speed fan fuse good, seems I can drive for hours and everything good, one hard pull, no fan. Can CCRM be intermittent, once car cools for 3 or 4 hours, fan works perfect. Trying to find diagram and procedure to disconnect fan plug, and somehow wire it to a relay to run high speed only with maybe a temp probe, but no luck there, haven't enjoyed the car in 3 years and has me baffled.
 

hotcobra03

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In here svt documents page

scroll down to service manual

on that paragraph icon on top left is the button for the full version manual

it only works on a laptop or better

in paragraph. (Hard copy)

click that. Has small version of manual with basic wiring in color

Did you replace fan?

when it’s at 230 and fan not on you need to test for power somewhere

that 3 pin is where I would have power leads and a ground lead these need to be tested when your having the issue

than you can tap into pcm signal at ccrm area to give that signal

not much involved.
Ac has some ties with power also which is another area to look at

side note

im in a shoe like this on my dodge
Fan works when it wants .

I now have ran jumper trigger wires to turn relay on

same spot the pcm would trigger

for testing.

I haven’t done much more yet
 

notagt

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Yes, fan is new, everything works good till hard pull..kinda hard with giant IC resvoir over the connector to test when car at 230, tank would have to come out WHILE it is overheating, gonna remove tank and test fan directly to battery, then crank car while cool, turn on ac and test at plug...but I know it will pass all these test, here in garage all systems work great, on the road all good, bury throttle one time..done, no fan period, by then everything to hot to get hands in there, gonna try hard wiring fan to harness, new ccrm and ECT, that will cover EVERYTHING in cooling/electrical except pcm...was even thinking of having it put on dyno to see if it does it.
 

notagt

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It had a new one..like I said, on my test ride all was good, did burnout, 2 miles later..no fan, 230...car cools, all good, that's why gonna try hard wiring 3 prong, or get a relay and temp control probe, and tap into high side of fan only adjustable by me, I see a temp, turn dial till fan comes on..on part I am sketchy on is to do that should I disonnet connector to resistor, or does that still need to be in the circuit for high speed to work..don't think so since I would wire relay and probe to fan with 3 prong disconnected...almost like wiring in an aftermarket fan
 

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