Fan/aircompressor not working... & overheating!!!

UltimateSVT

UltimateSVT

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Miami, FL(Home of the rust free MARK VIII's
MUST READ, MIND BOGGLING... WHAT THE HELL?!?!?
Ok guys, when I installed the 99 Mustang Cobra pump on my car back in January I noticed the radiator fan doesn't run when the A/C is OFF. As soon as I turn ON the A/C the radiator fan turns ON. My friend is a mechanic & told me that as long as I use the A/C, my car won't overheat. I've been using my Mark this way since January without an issue. I even drove it to the Keys last month without a hiccup (over 180 total miles).

This past Friday I traveled about 35 miles to a local car show here in South FL. with Marvin. The car ran cool, no problems. After 4 hours at the show, my girlfriend was tired & a bit hot from the nasty heat. I turn on the car for her & let it idle. Turns out that 6-7 minutes into the car running my girlfriend felt cold so she turns off the A/C but leaves the car running (she has no clue about cars nor guages)...

15 minutes later we all decided to leave & as soon as I hop in my car the needle on the letter "O" on NORMAL flips me out! I notice the a/c is off so I immediately turn on the A/C assuming my fan will run & cool off the car. The A/C blows VERY HOT! I turn it off, then on again & still hot, I get on the highway & the a/c started to cool. The car temp didn't start coming down until I traveled a good 2-3 miles. After driving the 30 miles on NORMAL temperature I get off the highway. The car immedeately starts to rise in temp. AAAANNND my A/C starts blowing HOT again. WTF?!?!?

I reach the house, pop the hood & notice that the fan isn't running & the A/C compressor is acting like if it was almost empty On/Off/On/Off, etc... I figured something electrical may be the issue between the A/C & the fan so I disconnect the battery. When I connect it again, I start the car & everything is running fine, compressor ran fine, fan started to run, etc...

The following morning I was leaving to the Keys again in my Mark VIII so I start the car & I notice I'm back to square one, same sh!t is happening. I risk it, go to my g/f's house 12 blocks away, the car only reaches normal temp due to the short distance but the A/C blows hot unless I go over 40mph. By the time I reach my house again the temp needle has officially gone over the "N", my display advises me to check the engine temp & there's water/steam coming out my reservoir. DONE! :mad::mad::mad:I had to leave to the Keys so I left in my truck instead of my car.

What the hell is wrong with my car? Fan? A/C compressor? Both at the same f*cking time? I'm fuming mad because I don't have cash to spend on the car. Once again my car has to sit while I'm unemployed due to it's issues.:mad:
 
VCRM bad? If it's getting hot and the fan isn't engaging then theres something wrong. Coming on with the AC is normal though. Could be a bad temp switch too possibly. Any codes?
 
You've got to start by scratch buddy check the fuses...im pretty sure you already checked em but just an idea. Secondary I dont think our cars are designed to run without thermostat and somebody with more knoledge might chime into this subject, that might be your issue. On my Cougar when I took out the thermostat it would cause my car to run hotter than normal. I put the t-stat back in and solved all my problems. Sometimes by not running a t-stat it causes no pressure in the cooling system and can cause issues with your headgaskets....then again im no genius but just something to think about. Also one more thing when the needle reaches the middle of normal the fans first speed comes on....then when you turn the a/c on its supposed to run on second speed.
 
Icarus said:
VCRM bad? If it's getting hot and the fan isn't engaging then theres something wrong. Coming on with the AC is normal though. Could be a bad temp switch too possibly. Any codes?
Click to expand...

No codes, no check engine light either... What's the VCRM?

02LS8Lincoln said:
You've got to start by scratch buddy check the fuses...im pretty sure you already checked em but just an idea. Secondary I dont think our cars are designed to run without thermostat and somebody with more knoledge might chime into this subject, that might be your issue. On my Cougar when I took out the thermostat it would cause my car to run hotter than normal. I put the t-stat back in and solved all my problems. Sometimes by not running a t-stat it causes no pressure in the cooling system and can cause issues with your headgaskets....then again im no genius but just something to think about. Also one more thing when the needle reaches the middle of normal the fans first speed comes on....then when you turn the a/c on its supposed to run on second speed.
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If it was a fuse issue, when I unplugged/plugged in the battery it wouldn't have worked. You may very well be right about the thermostat but howcome my car's been running cooler than normal? I do plan on installing it though, just another item to add to my list. I just wish I knew why the A/C is blowing hot & everything is happening together. Something doesn't jive!
 
yeah something doesnt make sense.....about your compressor turning on and off.....it could be low freon. When your freon is low it causes your compressor to turn on and off at a fast pace.
 
VCRM is mounted in front of the radiator. Small black box about a 6 X 6 and it looks like it has heat sinks on it.

I think I could fix that car for around $25.00.

The fan is going to come on when you turn on the AC and it's not going to kick on without the AC unless it gets hot enough which is usually right at the half way mark or a tad higher.

Get you a can of this below and add it while the car is running with MAX AC ON. Add it little at a time and the more you add, the longer the AC compressor will stay on. I think your 134A is low and this stuff fixes leaks. Mine was out completely and it took 3 cans but now it's cold cold and hasn't lost any that I can tell. It's had time to lose enough if I had a leak but apparently it fixed the leak.

94OutBack001.jpg
 
It sounds like your coolant temp sensor, the one if front of the intake, thats the one thats basically signals the fan to kick in, i work at parts place and see these kinds of probs alot, try with the engine running, disconnect the coolant temp and if your cooling fan comes on, thens its the sensor itself.
 
change small things first Alex. Like el Gordo says it could be the coolant temp sensor it triggers the fan i know this b/c I also replaced that in my Cougar. And its like an 8 dollar part at the parts store.
 
2 things haven't gone wrong. Your a/c is not working, because the engine is too hot. The VCRM will not allow the a/c to turn on. Once you get on the highway and have a speed higher than 47mph, there is enough natural airflow thru the radiator and condensor, that the engine cools and the a/c turns on. Once you go below 42mph, the fan is supposed to turn back on. Unfortunately yours is not, so the engine heats up and the a/c turns off. AS so, I say it is the VCRM and not the ECM coolant temp sensor. Reason being, is that the VCRM is seeing a hot temp and prohibiting a/c operation, but it is not turning on the fan. More than likely it is the cooling fan control circuit inside the VCRM that has failed.
 
Wow, lots of expensive parts to start throwing at this thing, eh? I wouldnt be worrying about your A/C issues atm, as they are a being effected by the fan issue you have. The A/C commands the fan to come on, to cool the condenser at the front of the engine. If that fan is not working, the pressure of your refrigerant gets high due to the high temp. The cycling switch sees this high pressure, and switches the compressor on/off as pressure rises and falls. When the system is operating normally, that switch stays closed. So don't worry about the A/C at the moment... Try jumping your fan just as a test and make sure it works all the time. Also a wiggle test wouldnt hurt while everything is connected as it is right now, grab the harness, with the a/c on and see if moving the harness around effects the fan. As for disconnecting/reconnecting the battery, I'm not sure why it would cause the fan to work, but modules normally behave like that so a VCRM isnt out of the question. If you jump your fan, I think you will see that you can drive the car and the a/c will work fine, if the fan isnt messed up itself. Check fuses in the engine compartment, I am looking at the EVTM manual, and it looks like they don't number the fuses in the engine compartment, but on a 95, it is in the middle row of fuses, 40amp 4th from the front. Just check and make sure the fuse is tight, and not corroded or anything. Let us know if you come up with anything.
 
And also... what did you install from a mustang in your car? The a/c compressor? That should have NO effect on how your stock fan works.
 
the only part you need to throw at the car is a vcrm. if it isnt the vcrm, i will pay your gas to come to the mark meet.
 
Sounds like a good deal to me! The VCRM by the way, as I can see in the wiring manual has 2 legs coming from the VCRM that splice into one at the fan, and then one ground. So basically what I am saying is your connector at the fan should have 2 wires. One side is when the VCRM tells the fan to cool the engine down, and the other leg is for when the A/C is on. If you have had to use the a/c function of the fan to cool the engine for this long, then it would appear that the engine cooling side of the VCRM has been dead for a while and now the a/c side is dead now too.
 
DieselDan said:
Wow, lots of expensive parts to start throwing at this thing, eh? I wouldnt be worrying about your A/C issues atm, as they are a being effected by the fan issue you have. The A/C commands the fan to come on, to cool the condenser at the front of the engine. If that fan is not working, the pressure of your refrigerant gets high due to the high temp. The cycling switch sees this high pressure, and switches the compressor on/off as pressure rises and falls. When the system is operating normally, that switch stays closed. So don't worry about the A/C at the moment... Try jumping your fan just as a test and make sure it works all the time. Also a wiggle test wouldnt hurt while everything is connected as it is right now, grab the harness, with the a/c on and see if moving the harness around effects the fan. As for disconnecting/reconnecting the battery, I'm not sure why it would cause the fan to work, but modules normally behave like that so a VCRM isnt out of the question. If you jump your fan, I think you will see that you can drive the car and the a/c will work fine, if the fan isnt messed up itself. Check fuses in the engine compartment, I am looking at the EVTM manual, and it looks like they don't number the fuses in the engine compartment, but on a 95, it is in the middle row of fuses, 40amp 4th from the front. Just check and make sure the fuse is tight, and not corroded or anything. Let us know if you come up with anything.
And also... what did you install from a mustang in your car? The a/c compressor? That should have NO effect on how your stock fan works.
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Dan, I will look into all of this in the next couple days. It's a 99 Mustang Cobra water pump just as NoLimit mentioned. I purchased it as a better option. It's a better pump.

jamie97lsc said:
the only part you need to throw at the car is a vcrm. if it isnt the vcrm, i will pay your gas to come to the mark meet.
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Jamie I better hope it's the VCRM so that I can fix it on my own without having to spend too much cash because I really can't spend a dime on the car right now. I'll be looking into this in the next couple days when time permits.

I have 3 job interviews between tomorrow & Wednesday. If I land a job, I'll have the cash very soon. I hope I can separate some time tomorrow so I can find the VCRM & figure out exactly what I must do.:confused:
 
i'd bid on that, there are a few others for the same years 93-95 for 175 and 199 on egay right now, people are getting crazy over these little pricks!!
 
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