94 2.3 coolingf fan and ac problem

[jeffwal]

just got this car used it nice n clean and run good for high milage, problme is cooling fan does not run pervious owner had it wired direct to power. so i reveresed that. installed new temp sensor and fan motor, new t stat just cause they are so fun to get at.

car does not overheat, i do not let it run long enough but temp guage will hit 280. a/c compressor does not run or turn fan on. i am wondering if i am looking at a relay problem. i have a new ac rel;ay but can not identify its location. there are 3 relays on the right side engine compartment, there are also some metal fuses in the fuse box that i have not identified either.

what should i chack next? anyone know location of the relay,

thanks jeff

[jeffwal]

found on problem guy at autozone gave me the sensor for the guage instred of coolant sensor. jumpered the wire and fan started . so now just the ac problem. anyone know where the relay is?

thanks jeff

[skibum1111]

before you go tearing into relays and such, check to see if the ac is charged. if it is below a certain pressure, the compressor clutch will not engage and the fan does not turn on. check the wires coming from the high pressure sensor, its on the line going from the condenser to the compressor. do your pressure check on the low side, the service port should be on the compresor. good luck

[nheuer]

Not to be the bearer of bad news but it could also be the ECM. My ECM is blown on the ac/cooling fan circuit.

[jeffwal]

ok so here is where i am at with the cooling fan...grrrrrrrrr
94 g/a with 2.3
replaced bad motor now it works with direct power,,
replaced sensors both one on what should be thermostat cover and one behind t stat cover
replaced t stat nice placement under the exhaust manifold

fan does not run at temp..... if i disconect the sensor wire at the tstat cover it runs? whats up with this car? im thinking its an ecm problem. when i disconect that sensor i also get check engine light.

any ideas? can a bad water pump do this? the lower hose is cold the upper is hot,, the fan does not run
there is no leaks or noises from the pump.
guage reads to the red line at 280 and stops gets no hotter or cooler, does come down some when i put on defroster. so much for a 600 deal car.

thanks jeff

[jeffwal]

any way to test the computer? or any indicator to tell me its that problem? this is an odd one for me never seen anything like this in al my time working on cars. i could always get an ecm and try it. the disconection of the sensor turning on the fan is bizzare it would almost make perfect scence if it was the ecm.

thanks jeff

[skibum1111]

Try this: Disconnect your heater hoses from the engine side, attach a garden hose to one end, see how much flow you get through the other side. I had a no heat, no cooling, overheating problem last fall, turned out to be a clogged heater core. Also burp the air out of the system, that will cause it to get really hot without the fan turning on and without the lower hose getting cold. The sensor on the water outlet is the one for your gauge, the other sensor is the one for the cooling fan. It sounds like the sensor is not getting hot enough to turn the fan on, which would explain the hot running situation. Its also possible that the head gasket is leaking, I just dealt with a bunch of problems related to that: overheating, radiator cool to touch, upper hose hot, lower hose cold, coolant in the exhaust and coolant in the oil. The last two symptoms happened recently, but I think the gasket was leaking since last fall when the heater core clogged up.

[jeffwal]

car has great heat, so the core is not plugged, i see circulation in the tank so seems like the pump os working. no leaks no af in oil. seems like i may have a ecm problem. everything else has beeen changed.

unless i put the t stat in backwards....... spring is toward engine cap end to hose side.... anyone know if that is correct?
yes its that stat by the water pump under the exhaust
jeff

[skibum1111]

when you put the thermostat in it should have gone in spring up. its the only way it fits on the ones i have done anyway. the ecm is programmed to turn on the cooling fan on the quad 4's at around 220 and run it until it reaches 200 or so.

[jeffwal]

ok so stat is right then. ordered an ecm today exchange priced at 120 so not to bad. ill have it tuesday hopefully that fixes this its driving me crazy.

jeff

[skibum1111]

Be careful if you have to swap the chip out of the ecm, they are really easy to break.

[jeffwal]

crap..ecm made no difrence, i must have a bad part damn auto zone....

is there a refrence for sensor ohms at tempature....


why does the fan turn on when i uplug the front most sensor? i get chcek engine and idle changes but fan runs... when i plug it back it it stops and check goes away..

jeff

[skibum1111]

When you unplug the sensor it tells the ecm that there is a fault, it shows a code to indicate where the problem is, and it kicks the fan on in case of a bad sensor and an overheat situation, also changes the idle usually up to circulate coolant better.

[jeffwal]

any idea what to check next? the fan does run with sensor disconected so not fused link. where is fan relay maybe that is bad. i have not found that yet?

thanks