A/C Relay

[SIMid]

Hi everyone,

My A/C is always been a hit and miss lately and yesterday, coming back from the CBD, the A/C went bye-bye. The thermos are working constantly, but not blowing cold air out of the vents. I did notice that the relay in the fuse box was not clicking like it use to when working.

Which relay is it? Thought I'll replace it before trouble shooting somewhere else.

Thanks.

[Ron]

"The thermos are working constantly, but not blowing cold air out of the vents."
No comprende.

[SIMid]

"The thermos are working constantly, but not blowing cold air out of the vents."
No comprende.

When I turn on the a/c, it's blowing cold and the thermo fans run constantly. I can also hear the relay behind the passenger seat clicking in the fuse box. But when the cold air stops blowing (just not cold), the thermos still run, no clicking noises from the fuse box. So i'm just seeing which relay do i need to change for the a/c. If i change the relay and she still plays up, then i'll look elsewhere.

[WelmoedJ]

Thermos??... Is that how you call the cooling fans? Or do you refer to the blower fan?

Cooling fans: check your circuit breaker first.
There are two together in the relay compartment in the relay row closest to the passenger seat.
The one with the two wires is for the fans.
It may be defective, Amp value should be 40 if you have original cooling fans.

If you fan fail relay is replaced by a three wire jumper with 2 20A fuses, you can safely replace the circuit breaker by a piece of 6 Ga wire between the Fan and Fan Fail relay sockets.

Next if you Fan relay is suspected to be defective, you can swap it for an alike relay of you have those in your spares (even an old, but found good one will do for testing).

When you explain, please use Fan or

[Bitsyncmaster]

I think what your saying is the AC works at first and then the cold air stops comming from the vents. But your AC compressor is still engaged. If that is so, it sounds like you may just be low on freon or you have moisture in the system that is turning to ice.

[SIMid]

Sorry, what I meant was the fans on the radiator are constantly running when the A/C is switched on. She blows ice cold and then just stops. All fans are running (radiator and interior), just not cold and the relay stops clicking in the fuse compartment.

Just thought I'll change the relays over, but looks like I may need to take it to an A/C guy then to get it looked at as well.

[SIMid]

Just looking through the electrical manual and all the relays, which one controls the A/C, the one that "clicks"?

Fan Fail Module? or Cooling Fan?

[Bitsyncmaster]

Next time it stops blowing cold, open the engine compartment and see if the compressor is turning. If it is turning your problem is not electrical.

[SIMid]

Next time it stops blowing cold, open the engine compartment and see if the compressor is turning. If it is turning your problem is not electrical.

Cool, I'll check it next time. Thanks!

[Ron]

Next time it stops blowing cold, open the engine compartment and see if the compressor is turning. If it is turning your problem is not electrical.+1

If it fails Dave's test above, try bringing 12V straight to the compressor coil wire (briefly). If it then runs, either the compressor coil is getting weak, or more likely, it's not getting power from the Pink wire. If you find there is no power there, try checking for power/jumping the low pressure switch (screwed in to the silver canister in the passenger front wheel well) Pink wire to Pink-Orange (usually). If no power on the Pink-Orange, check it at the mode switch. If there is, you probably need freon (or a new pressure switch).

The mode switch has power since it is the source for the relay(s) that run the blower you say is ok...This, in any case, means you can forget about "relays" being the problem as there are none between the mode switch and compressor.
That being said, I'm curious as to which relay you hear clicking while it does work....and exactly what kind of clicking (ie random, a few, quick, etc???).

[SIMid]

That being said, I'm curious as to which relay you hear clicking while it does work....and exactly what kind of clicking (ie random, a few, quick, etc???).

When I turn on the A/C, I can hear a click in the Relay department and while running, I would hear the occasional clicks every so often, maybe 10-30 secs between them. When she stopped blowing cold, I noticed the "clicking" had stopped. Hence why I thought it could be a dodgy relay. So maybe not then ........

[Ron]

Maybe, have someone turn the ac on and off slowly so you can maneuver to locate it easier....but don't let that (me ;-) side track you!

P.S. Ask if anything wasn't clear!

[SIMid]

Maybe, have someone turn the ac on and off slowly so you can maneuver to locate it easier....but don't let that (me ;-) side track you!

P.S. Ask if anything wasn't clear!

*L* Was actually thinking of that. I only drive her occasionally, but there's a few car shows coming up and it's summer here so when the a/c stops, gets a bit toasty inside.

Definately will get an extra pair of hands and eyes on this and let you guys know. :)

[David T]

Sounds like you have 2 problems. The clicking noise is the cooling fan circuit breaker popping. The A/C blowing cold and then not probably is because you are low on freon because of leaks.

To fix the clicking circuit breaker get the "Relay Upgrade Kit"

To fix the low freon, replace the 3 hoses and refill with R-12.

If the mode switch is hissing get a rebuild kit for it.

David Teitelbaum

[Ron]

I don't see it being the cooling fan circuit breaker popping since he said "the fans on the radiator are constantly running when the A/C is switched on".
I'm with ya on the low freon, so far...I guess a good question would be how long does it have to sit before it will cool again...or, does it come and go or do you have to shut it all off.
Of coarse a hissing mode switch could screw with the flaps, but not the compressor...

He's all over it now :smile:

[Farrar]

I don't see it being the cooling fan circuit breaker popping since he said "the fans on the radiator are constantly running when the A/C is switched on".

Perhaps he meant the blower motor circuit breaker.

[SIMid]

Just thinking (Im at work atm), if the clicking stops, then technically shouldn't one of the fans stop working? Cause they all are working/running (radiator fans and interior fan), but just not blowing cold.

[Ron]

Perhaps he meant the blower motor circuit breaker.
No Diff'


...All fans are running (radiator and interior)...

[Ron]

Just thinking (Im at work atm), if the clicking stops, then technically shouldn't one of the fans stop working? Cause they all are working/running (radiator fans and interior fan), but just not blowing cold.That is why I was curious and said don't get off track LOL

Either you aren't catching them going off, or more likely, it is something indirectly/un-related....to much unknown yet to even guess.... Cooling fan circuit original?, etc

[SIMid]

Cooling fan circuit original?, etc

I believe so. Toby had upgraded the fans with Bosch ones, and thats all I know. Unless he has done some alterations that I am unaware of.

[David T]

Typically the clicking behind the passenger is not a relay, it is the CB. If he is low on Freon the fans will stop running when the compressor stops running unless the Otterstadt is also turning on the fans (but they won't run anyway if the CB is clicking off!). He needs to get the relay upgrade kit and is also low on freon. This is all assuming his system is stock. I mentioned the mode switch because if he needs the upgrade kit chances are his mode switch is hissing. Not because they affect each other, if one isn't done the other usually isn't either. General lack of maintaince. He probably needs hoses too. All too often an owner hopes it is just some minor little thing and that's all they need, like a relay or a fuse or maybe a little shot of gas. Wishfull thinking. Besides, all it takes is a look to know if he needs the relay upgrade kit. For testing purposes you can just jumper the CB and see if the clicking goes away.
David Teitelbaum

[SIMid]

I sent Toby an email a few days ago regarding spiking of current through the Auto. He replied back.

" I looked back through all of the records, and the only thing that were done that would affect the radiator fans were that the fan motors themselves were replaced with new Bosch motors (not the high torque low draw fans from DPNW) and the relays were freshened up. There was no change to the wiring noted in the records."

[Bitsyncmaster]

The AC compressor will normaly cycle on and off unless it's really hot outside or your engine is just at idle speed. When it does cycle (the low pressure switch controls this) the compressor clutch, the cooling fan relay and the low pressure switch itself can make that loud click.

[SIMid]

Just a quick update.

My Autoelectrican mate had a quick look over on the weekend as I dropped past to say hello. He couldn't help it and decided to poke around.

Did think that she may had been a touch low on gas, but I said to him that when she blows cold, she's really cold. If she was losing and has lost some gas, surely it would not be cold anymore.

So we fired her up and she was blowing ice cold.

The compressor was good and clicks on and off (showed me what the hell you guys were talking about :lol: ) He felt the pipes coming off the compressor, top one was cold, the bottom one was hot, all good. The condensor under the passenger front wheel well was frosting up, which was great news too. Then the temp started to get warm like always after the system had been running for a brief period. He worked out that the Hot Water Valve was not closing. We crimped the hose and the air coming out gradually got colder and colder. He was actually impressed with the system, said it was probably an over kill for such a small cabin. :lol:

So when I rebuild the Auto, I'll change that part over, and probably the hoses as well.

He also made a comment regarding the BOSCH K-Jetronic which I'll leave for another thread. :lol: Basically said it was a pretty good system for what it was.

[David T]

The only time the heater valve is closed is when you have the mode switch in MAX. The coil should NOT be frosting over, it SHOULD be sweating. You are low on refrigerant. When you are low but there is still enough to trip the low pressure switch and get the compressor to run but the coil will get VERY cold. That is because the low pressure side is getting too low on pressure and the temperature of the coil gets below 32 degrees F. You don't need much refrigerant. Tell your mate there is also a small screw on the low pressure switch in between the terminals. Normally it should not be touched but if necessary it can be turned a little. Should only be done when you have a set of service gauges on to monitor the system pressures.
David Teitelbaum

[SIMid]

The only time the heater valve is closed is when you have the mode switch in MAX. The coil should NOT be frosting over, it SHOULD be sweating. You are low on refrigerant. When you are low but there is still enough to trip the low pressure switch and get the compressor to run but the coil will get VERY cold. That is because the low pressure side is getting too low on pressure and the temperature of the coil gets below 32 degrees F. You don't need much refrigerant. Tell your mate there is also a small screw on the low pressure switch in between the terminals. Normally it should not be touched but if necessary it can be turned a little. Should only be done when you have a set of service gauges on to monitor the system pressures.
David Teitelbaum

Thanks for that David,

Once I change the heater valve, I'll get him to check the level and go from there. It was just one thing he managed to work out.