A/C problems....

[toddious]

so here's the deal. i started the truck, and had the a/c running, and it was working fine. i started loading stuff in it, and spent about 10 minutes outside the truck, and when i got in, it wasn't blowing the cold air out. i turned the air up, and it didn't do anything. there was cold air slowly coming out of the vents, but not really blowing out. I turned on the rear air, and it was blowing out cold and fast, but the front would not respond. is it the blower for the front? is there such a thing? i know nothing about a/c. i know it seems to there is cold air, but it will not blow out the front vents. any help? thanks. todd.

 

[toddious]

anybody?

 

[zx6-guy29]

sounds like your front blower motor to me, but check and make sure it isn't something more simple like a fuse or realy before you run out and get a new blower motor. Also check if the system needs charging

 

[toddious]

i checked fuses, and all the ones associated with a/c and the blower are fine. i think the motor must have taken a crap. how hard is this blower to replace? it's probably in the dash and a complete PITA. anybody?

 

[budwich]

As the previous poster said.... check the fuses and RELAYS. It sounds like you only did the fuses. There is a blower relay that must operate otherwise you a SOL.... use the one for your working rear to see if the front one is bad.

 

[Derbytown]

Turn it off a little while and see if it blows then. The front evaporator coil might be frozen up due to lack of air flow across it. JMHO!. Be safe.
Derbytown

 

[toddious]

there is a large 50 amp fuse in the black box under the hood. is this the relay you are referring too ? i didn't think that any of the other relays in that box were for the blower.

 

[budwich]

No... its not a fuse.... its a relay. You should hear it click when it gets pulled up.... alternately, you should measure voltage on one side and then the other when it pulls up.... this is the "juice" that you need to run your front blower motor. It is in Aux Relay Box #2.... on the right front of the engine comp... under the air intake / filter.

 

[jp450]

There is a resistor in the blower motor itself. Its on the lower right hand side of the motor. I have seen many Ex's have these go bad and then no front blower motor. Usualy you will get low and hi. A new resistor is about $27 from the dealer and can be replaced in about 10-20 min.

 

[toddious]

No... its not a fuse.... its a relay. You should hear it click when it gets pulled up.... alternately, you should measure voltage on one side and then the other when it pulls up.... this is the "juice" that you need to run your front blower motor. It is in Aux Relay Box #2.... on the right front of the engine comp... under the air intake / filter.

ok, few questions....

relay box #2.... under the intake/filter, so on the passenger side? in the manual it gives the relay locations for the box on the drivers side just behind the battery, is there another location?

also, where would i take multimeter readings from?

I have no blower, neither HI nor LO, so does that elimitate the resistor from the equation? obvsiouly buying a new blower is my last resort. thanks, todd.

 

[budwich]

one, two, three, .... I need to count and take a breath...

first relay box NUMBER 2 is on the RIGHT side of your truck.... according to my "reference". relay box number 1 is on the left side.

You are looking for #2. At the relay, you should find two BK/LG wires... both should have 12v on them. A PK/W wire should see nothing when the relay is not pulled up and then should see 12v when it is. This 12v goes to your blower motor (among other things). There is also a high speed relay in the same box that switches the motor to high and basically switches out the resistor packs.... so if you switch your blower to high, it should operate without worrying about whether the resistors are good or bad (assuming that the relay operates also). Basically, if you can't get the high speed to happen, you need to check the "circuit" that I just "described". I would also think that you should see some resistance measured thru your motor (as a check) if it is "functional". Hope that helps a bit more. Good luck

 

[toddious]

ok, well i finally got into the aux relay panel #2, and didn't have working relays to swap in place, so: i took the relays out, and put tried them in relay box #1 for the winshield wiper hi-lo (since it is the same relay).

both relays from panel #2 worked fine in the other position, which makes me assume that they are operating fine.

I have not gotten to check the resistor located on the blower itself, as i don't know exactly where to look for this. ANYONE HAVE A PICTURE PERHAPS? i don't even know what the blower itself looks like, or it's location.

even if that resistor is bad, though, shouldn't the a/c still work in high? when i turn it on, there is absolutely no blowing, even on max a/c, and the compressor seems to be kicking on and off.

 

[budwich]

You are getting there but not quite. Checking to see if the relays work somewhere else is a good check to see if the relays work themselves. What it doesn't check is at there "normal" slot in relay box #2. As you indicate, in high, the resistors aren't in the circuit. You need to ensure that the relay pulls up in the relay box #2 and that voltage is getting thru the contacts there (ie. you see volts in and volts out). If the relay doesn't pull up and you have no voltage, then fuse #6 (I think) is bad. If there is voltage, then you motor speed switch on the dash is bad or doesn't have a ground at the appropriate pin. The ground (G100) comes from the left rear side of the engine compartment.

 

[toddious]

i switched out both relays from in panel #2 with working relays, but had no success.

the switch seems to be working fine, because when i am in "automatic" air mode, and turn the switch, it changes o ut of automatic mode (yet still not turning the blower on)

also, the rear blower still works, yet with the a/c on max, it still doesn't seem to be blowing out very cold, and the compressor seems to be kicking on and off. is the front blower required to get air to the rear blower? and would the compressor kick on and off without the blower sucking air?

 

[toddious]

bump.... i need some help please.

 

[zx6-guy29]

i switched out both relays from in panel #2 with working relays, but had no success.

the switch seems to be working fine, because when i am in "automatic" air mode, and turn the switch, it changes o ut of automatic mode (yet still not turning the blower on)

also, the rear blower still works, yet with the a/c on max, it still doesn't seem to be blowing out very cold, and the compressor seems to be kicking on and off. is the front blower required to get air to the rear blower? and would the compressor kick on and off without the blower sucking air?

Compressor kicking in and out often definitely means the charge is low. It is a built in safety feature so it doesn't seize. If it gets much lower the compressor won't engage at all. I had the same problem, but without the blower problem.

 

[budwich]

toddious.... I not sure what you mean by " changed out both relays with working relays and had no success". Does that mean that the relays operated but you still had no fan or the relays did not operate or you didn't check to see if it operated???? You have to make sure that the relays are operating either by "sound" (not reliable) or my meter.... just changing them isn't really helping to tell us the state.... although I guess it helps a bit that you know the physical relay is good.... you need to ensure that it is operating in the panel that it is supposed to be in.

No the front blower is not required to get air to the rear. I though in your first post that the rear air was really cool???? Anyways, I think if you aren't taking the cooling from the evaporator (?) with enough air flow then the system may cycle and / or freeze up. But as mentioned, usually cycling problems tend to reflect lack of freon.

 

[budwich]

actually, I just re-read your last post about the "automatic air" which I guess means you have EATC. In this setup, the blower speed motor controller contains everything including the resistors and stuff (at least from my reference). Unlike the "basic" AC / heater stuff, where the resistors are switched out for high, I suspect the blower speed motor controller does something else and is probably a good candidate for your troubles.

I guess the first question should have been what type of AC do you have. However, the blower motor relay still has to function (ie. operate) to get the fan to turn on regardless of system type.

 

[toddious]

ok, i assume i have the EATC, which has the automatic air function.

the air in the back seemed colder, but after further evaluation, i still don't think it is "conditioned" air. the compressor seems to be kicking on and off, not producing cold air.

there is a chance that the freon is empty, which would stop the compressor, but would this affect the blower? or cause it to go out?

the blower works in neither high or low.

by "changed out the relays" i meant replaced them with new working relays. so you're saying the relay box itself could be whats bad? and how would i test the speed motor controller?

 

[budwich]

Thanks for the clarification on the relays. First.... no the compressor cycling has no way of stopping your front fan from working (I think...). The cycling on the compressor is another problem which as stated is likely low freon levels.

Back to your fan... no the relay box is not bad (unlikely)... what it means is you are not getting the right "conditioning" to cause the relays to operate to cause the fan to operate... understand??? In your EATC case, there is only one relay (sorry about very early posts which I thought was about "basic air conditioning / heating"). That relay is the blower motor relay (aux relay box #2). It operates when you key is in run. There should be 12 v on BK/LG and ground on BK wires at that box when your key is in "run". The relay should operate (ie. you should hear a click there but verify with a meter). That is straight forward and a "go / no go" condition. The "switch contacts" of that relay cause the blower motor to get "power". This power (12v) is another BK/LG wire and comes out of the relay on PK/W to your blower motor. This should also be checked.... before operation 12 V on BK/LG and 0 on PK/W and when operated 12V on PK/W. If you do not see this, your blower motor has no chance of running. If you do see this, then all that is left in the circuit is the blower motor (could be bad... I doubt it but...) and the blower speed controller which could be bad (good candidate) but not necessarily as it gets its "commands" from your EATC control module. Hope you can follow this. Having said the above, there is some possibility that your cycling compressor "status" might be feedback to your EATC control module via the PCM (power control module) which "appears" to have some "knowledge" of such events.... I don't know about this .... just my "interpretation" of the schematics.

As noted in the previous explanation, it is likely that your speed controller is a problem but you should check the states as mentioned before going there.... or if you want to throw some money around, just replace it and see if it solves your problem.