Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
check fuse # 9 and 13 in the fuse box they should be a 10 and a 40 amp fuse. on my diagram it shows a separate relay for the fans than the ac compressor. let us know how those fuses are in the fuse box. also try swapping relays for right now...
The following user(s) said Thank You: Tyler, Monde
are you getting power to pins 2 and 5 of the relay?? also have you tried jumping the relay with a jumper wire to see if you have a control side problem or a load side issue?
Monde wrote: The relay is the same one that turns on the ac compressor. The ac compressor is engaging when the ac is on. The only thing I could see is the G/B wire going into the fan motor is open
It looks like there is one relay for the fan ( e66 cooling fan relay), and one for the a/c compressor clutch (e 30 a/c relay)
Different fuses feeding each relay.
The relays have different numbers, so they can't be the same one.
Also, if there was more being powered by either relay that wasn't shown on the diagram, there would usaly be a dotted line coming off the relay to indicate such.
Is the fuse that you said shows ground on each side on either one of those relays?
You could try jumping power to the g/b wire either at the relay or at the fan to see if it comes on. Or if you have a scanner, you may be able to do it in a bidirectional test.
Does this have 1 electric fan and 1 mechanical fan or 2 electric fans or third case of 1 electric fan ? The reason I ask is that depending on which fan style this has there is a high speed and low speed low speed is on any time the ac is on and high speed is on when the pressure switch senses higher pressure in the high pressure side of the ac system an Under filled ac sys system won't turn the high speed fan on as pressures would never get high enough...
Not that you still need to do this just so you know how. To use a dvom as a jumper you set your dial to amps (usually just a A and the DC symbol of a solid line with a dotted line underneath) and move your positive lead to the amp plug then you can hook your ground to B+ and red lead to load that way if you do accidentally Ark it will blow the replaceable (usually 10 amp) fuse sometimes located inside the dvom depending on brand also it doesn't matter which lead goes to battery it will just read a negative number if leads are reversed
As a word of caution don't forget to move your positive lead on your meter back to volts and ohms plug before shutting down your meter you will experience a huge flash of light and a blown fuse if you leave it in the amps slot while testing voltage!!!
I couldn't find a diagram to it so I'll explain this as a general if it is a 2 wire it's a 1 speed fan. if it has 3 or sometimes 4 wires it's a 2 speed fan in the case that it is a 1 speed fan it will be on anytime engine temp is above a given temp usually around 195 but can vary from vehicle to vehicle and will also be on anytime the air conditioning is running the 2 speed fan version will turn on when engine temp reaches a certain limit and then the high speed fan will come on if it goes a few degrees higher than that the ECM controls both of these through 2 different relays usually . Same for air conditioning low speed fan will be on anytime the AC is turned on and it uses the high pressure switch to turn on high speed fan to keep the pressure from going over the high limit switch . A couple things can cause the high speed fan not to come on 1 the high pressure switch could be bad (can verify with a AC manifold set ) 2 low pressure in the AC system also checked with manifold set. Or 3 possibly a wiring/relay problem that we can trace but we want to verify you have a problem before we go looking for a problem so pressures should be checked prior to electrical testing (since you said you can turn it on at high pressure switch I doubt you have an electrical problem)
Sorry been busy today .Hmm that's peculiar ok when you bypass the switch do you just use a jumper wire from pin to pin on the connector or do you use an external power source like a power probe
It looks like the ECM or the triple pressure switch can activate the relay. So even if the pressure switch was junk, the ECM would still have control when certain inputs are received.
An open on the RFRI wire from the ECM to the relay would set a DTC as noted by the diagram legend. Can you check the ECM or HVAC module for related trouble codes? Maybe even activate the fan from a scanner?
Is there a problem with the A/C system? Is it not blowing cold? The condenser fan on this vehicle is only designed to come on when needed. It is totally normal for this fan to stay off most of the time. The regular engine fan will pull enough air through the condenser. Under normal conditions it would take idling in a hot and humid day to put enough of a load on the A/C system to turn that fan on.
The fan is controlled by the pressure switch on the receiver dryer when it detects high enough head pressure. Not sure on the spec but expect 240+ PSI. If it doesn't turn on and the system isn't blowing very cold then the most likely cause is a low level of refrigerant. If it's low then it'll never reach a high enough pressure to trip the pressure switch to turn on the fan. 90% of poor cooling performance problems are caused by low refrigerant.
When the pressure switch does detect high enough pressure then it'll close a circuit allowing ground to the control side of the condenser fan relay. That then supplies power to the fan motor. If you want to test the fan manually then unplug the relay and supply power at pin 87. Most relays have a little wiring diagram on them. If you check pin 87 with the relay unplugged you should see the ground going through the motor because it's an open circuit. Applying power there will turn on the fan if everything is good. Otherwise if you want to test the rest of the system then turn the A/C on max cold, blower on full blast, open all the doors, let the system operate for a couple minutes to circulate the refrigerant then put a piece of cardboard in front of the condenser. This will cause the pressures to spike and should allow it to get high enough to trip the pressure switch and turn on the fan even if the system is low on charge.
A quick and dirty health test of an A/C system is to turn the A/C system on max cool, full blower, open all the doors then grab the two lines at the compressor. If everything's working as it should then one should be quite cold and the other should be hot. Ambient air temp will have a huge affect on this. If it's lower than 70F out then the two hoses will be closer in temperature to each other. If it's 90+F then the suction line should be uncomfortably cold and the discharge line should be uncomfortably hot. Again, this is a quick and dirty test. It will not match a set of gauges or pulling out the refrigerant to see what's actually in there.
Also I'd really advise you to stay away from those junk top up cans. A lot of them contain garbage sealants that I've seen take out compressors but they'll also contaminate your refrigerant. Refrigerant is required to be 98% pure R134a. If it's not then it can't be pulled out with a regular A/C machine. Otherwise it would contaminate the machine. And them things are expensive. So it would have to be pulled out into a junk bottle. Not all shops are setup for this and it'll cost extra. Top up cans also make it very hard to put in an accurate amount of refrigerant. Systems are very sensitive to the refrigerant level. Both too much and too little have a very negative effect on cooling. And lastly, top up cans don't do anything about air or moisture in the system. Both air and moisture have a HUGE effect on cooling ability. If you don't evacuate that out then you'll never get back to full cooling performance.
Heh, you can chalk me up as still being a bit of a forum newb I posted after reading the first page and didn't realize there were 4 pages of replies so that post might have repeated some stuff said earlier.
But ya, do not expect this fan to come on right away. Fixed orifice tube style systems will rely more on fans. This system uses a thermal expansion valve (TXV). If it's not a very hot day and there's not much of a load on the A/C system then the TXV will be able to regulate the system all on its own and won't have to cycle the compressor very much at all.
Ya, it'd be great to test that gauge on a separate vehicle to see if it's working. You could have a blockage in the system. That would make the compressor make noise for sure. But it's unlikely to have it match your conditions. A lot of other things would also have to happen. It's possible that maybe you have a low charge and the evaporator temperature sensor is faulty keeping the system going when it shouldn't? If you didn't have enough refrigerant in it then it wouldn't have anything to cycle the oil which would starve the compressor of lubrication. But again these are reaching for less likely scenarios.
Your system uses a thermal expansion valve. Some systems with TXVs can take a few minutes to equalize the pressures. But again, you shouldn't have 0psi on the low side... I would definitely suspect an issue with your gauge. Or maybe even with the schrader valve in the low side port.
Generally speaking it's not good if the compressor is making abnormal noise. It almost always means eventual replacement.
But ya, with something like this you really need an accurate pressure reading. The thing to do would be to get a reading of it under light load. Blower fan on low with all the doors and windows closed. Record those readings then crank the blower to full speed, set to recirculate and open all the doors. That'll put a way bigger load on the A/C system and see if the compressor can keep up.
Yeah, for sure. You especially don't want to use a leaking set if you're using it to put new refrigerant into the system. You'll get air in the system for sure. There's nothing worse than trying to diag something and then you find out a piece of your equipment stopped working!
The ECM is going to suppy ground to turn on the fan when the engine starts getting too hot for the main to keep up. So it's just used as an auxillary fan for the coolant system when needed. If it's needed for the A/C system then it'll be turned on from the pressure switch.
Topic Author
I posted after reading the first page and didn't realize there were 4 pages of replies so that post might have repeated some stuff said earlier.