Aircon problem!

[ajcooke]

Hi there - I've a 95 2nd gen 4runner 3.0 TD


My aircon works great - icy cold blast of air - but unfortunately only when it's not hot outside!!!
When the exterior temp gets really hot it stops working.

I've had the system checked for leaks and recharged.
The belt isn´t slipping and the clutch engages without probs when I press the a/c button.

When the aircon is working, one of the metal pipes going into the aircon unit (the bit with the belt attached on top of the engine - sorry don´t know my way round it yet) is hot and one is icy cold - I assume this is how it should be.

When it´s not working both pipes are very hot.

Anyone know what´s going on? Don´t know if this problem is a mystery or something bleeding obvious.

Just driven down to Mauritania from Spain and am heading south to Senegal tomorrow. It´s getting hotter and hotter and I´d love to get the aircon working properly!


Thanks for any help. :

[ajcooke]

okay so a local mechanic has helpfully pointed out that my aircon fan was not turning. I've tested the fan by connecting it direct and it works fine. The cables lead back to a small fuse box with 2 relays called CDS FAN1 and CDS FAN2 wit5h a 30A fuse in between them. If I remove either of the relays and stick a jumper cable from the battery + into terminal 3 of the relay socket the fan goes on. So, do I have a dodgy relay or is it somewhere between the relay and the switch? How do I check them? I have a voltmeter! If you can help, thanks.

Here I've attached the relay test from the manual - sorry to be an idiot but I don't understand what I need to do! What do constant, B+ continuity etc mean and how do I test? Thanks

[bowella]

Have you got a Multi-meter or just a volt meter?
I can tell you how to test the relay with either meter's but the way you do it will differ between using the multi-meter to using the volt meter.
Regards, John.

[Diezel Weazel]

okay so a local mechanic has helpfully pointed out that my aircon fan was not turning. I've tested the fan by connecting it direct and it works fine. The cables lead back to a small fuse box with 2 relays called CDS FAN1 and CDS FAN2 wit5h a 30A fuse in between them. If I remove either of the relays and stick a jumper cable from the battery + into terminal 3 of the relay socket the fan goes on. So, do I have a dodgy relay or is it somewhere between the relay and the switch? How do I check them? I have a voltmeter! If you can help, thanks.

Here I've attached the relay test from the manual - sorry to be an idiot but I don't understand what I need to do! What do constant, B+ continuity etc mean and how do I test? Thanks

Given what ya said above, could ya not fit up a temporary link with wire, Fuse holder n a switch (All temporary mind)

There's always a Payback .... But don't expect a Warning !!!!

[NiftyNev]

Have you checked the thermo fan switch?

Nev

[ajcooke]

Thanks for the replies.

John, I've got a multimeter - it would be great if you could talk me through it.

Otherwise I'll give shorting it a go;

nifty - what is the thermo fan switch?

Thanks!!

[bowella]

OK, first set your multi-meter to the ohms setting,
Put one wire from the meter to terminal 1 on the relay and the other wire to terminal 2 on the relay, look at your meter and it should read a few ohms resistance, I don't know how many ohms it will read but it should read something, if it is a digital meter you should see the numbers change when you touch the two terminals, or if it is one with a needle you should see the needle swing across.
Do the same again to terminals 3 and 4 and you should get the same result.
If all is ok with this test then go on to the second test.
Take a piece of wire and connect it to terminal 1.
Do the same to terminal 2.
Make sure your two wires are long enough when connected to the relay to reach both the battery terminals.
Connect your multi-meter, still set to read ohms, to terminals 3 and 4.
Connect one wire from the relay to the negative terminal (-) of the battery.
Whilst watching the meter, touch the remaining wire to the positive (+) side of the battery.
When you touch the positive wire to the battery you should hear the relay click and your meter should then read 0 ohms or the needle should swing the other way.
If this happens as described the relay is working correctly, if not then it is faulty.
If the relay tests out OK, then I would check the the temp sensor for the fan, I am not sure where it is on the 3.0 ltr but if it is the same as the 2.4 it will be on the housing where the coolant filler cap is, there might be two sensors there, one is for the temp gauge and the other for the A/C fan, if you pull the wire off of the sensor switch the fan should start, you must have the ignition on, if not try the other switch, make sure you have replaced the relay first !!

Hope this helps, if not post again and I'll try to explain it further.
Regards, John.

[ajcooke]

Thanks - relays all checked out - turns out it was a dodgy earth coming off the fan - all sorted now - just need to sort out the tracking after driving into a pothole - still it's amazing what an African mechanic can do with a length of fishing twine and a tape measure!!