A/C issues - Td5 and 300 Tdi

[travelrover]

Hi all

The recent warm and humid weather has highlighted some A/C issues I am having. My Td5 is now only pumping out warm air (well its hot really) no matter what setting the dials are on. Usually a fraction under max cool and full fan. But over the past few weeks or so even after being running for 30 mins there is no discernible cool air coming out of the vents. In the cooler temps it seemed to work ok but not brilliantly. I have owned this one since new (MY99) and don't recall the A/C ever having been serviced. Maybe now is the time!

With the 300 Tdi ('96) the A/C was working (albeit with a small leak in one of the pipes) but now is completely dead. I have replaced the fuses in the main fuse box. (Are there any under the bonnet?) but no change still dead. All the wiring I can see appears to be ok but without isolating and jumpering past sections I cant be sure. Could it be the switches have failed after 23 years?

Any guidance/suggestions would be appreciated.


Cheers - Simon

[86mud]

Hi Simon

I am unable to help you with the TD5 apart from go getting it serviced which includes a regas, new receiver/dryer and a check for leaks.

However with the 300Tdi, there is a mega fuse on a small black box on the fire wall (engine bay side) near the heater box. Check that all electrical connections are clean on fuses and relays. My 12 month 1998 300Tdi Defender Air Con has a relay tucked behind the air con unit against the firewall and the connection to this was found to be loose.....this involved removing the entire under dash unit.

I have found that 300Tdi Defenders all seem to have different models of under dash air con units fitted and also the location of the fuses and the two relays vary between the battery box and the firewall (next to the main fuse box) My model has the air con fuses plus two relays on the firewall next to the main fuse box. I have not seen this on any other Defender.

Good luck

[travelrover]

Hi Simon

I am unable to help you with the TD5 apart from go getting it serviced which includes a regas, new receiver/dryer and a check for leaks.

However with the 300Tdi, there is a mega fuse on a small black box on the fire wall (engine bay side) near the heater box. Check that all electrical connections are clean on fuses and relays. My 12 month 1998 300Tdi Defender Air Con has a relay tucked behind the air con unit against the firewall and the connection to this was found to be loose.....this involved removing the entire under dash unit.

I have found that 300Tdi Defenders all seem to have different models of under dash air con units fitted and also the location of the fuses and the two relays vary between the battery box and the firewall (next to the main fuse box) My model has the air con fuses plus two relays on the firewall next to the main fuse box. I have not seen this on any other Defender.

Good luck

Thanks 86mud, yeah I thought there was one big mother fuse in there. The two I changed In the main fuse box were a 20A and a 5A (slots 18 & 19). I will have a look on the weekend under the bonnet. I think the Tdi unit is an AMC as the controls are identical to a 300 Tdi single cab I bought ex Calvert Expedition in 1996 and that had a separate manual for the a/c which from memory had a wiring schematic also. That went when I sold it in 1999 unfortunately.

I will try and find a good a/c service place for the Td5 but there are not so many around these days!

Thanks again.

[HowardSmall]

My 99 TD5 was doing the same. Turned out to be a leak in the condensor. When that was fixed it turned out to be the friction fan. When that was fixed it got gassed up with total cost (including second hand condensor) of $1350 and worked fine for a week! Turned out the seal on the compressor shaft was leaking and I am now looking for a compressor. Point of this post is that it can be any number of things and as you fix one the pressure in the system is higher so another shows up, etc.

As an aside, I would love to know the model and part number on your compressor (mine is unreadable) so I can be sure what I am looking for.

Howard

[travelrover]

My 99 TD5 was doing the same. Turned out to be a leak in the condensor. When that was fixed it turned out to be the friction fan. When that was fixed it got gassed up with total cost (including second hand condensor) of $1350 and worked fine for a week! Turned out the seal on the compressor shaft was leaking and I am now looking for a compressor. Point of this post is that it can be any number of things and as you fix one the pressure in the system is higher so another shows up, etc.

As an aside, I would love to know the model and part number on your compressor (mine is unreadable) so I can be sure what I am looking for.

Howard

That’s the joy of owning Defenders Howard. Will see if I can find a part number.. lucky the vents are there to provide some air flow :-)

[Michael2]

On my 97 Tdi the AC controls were in the battery box. Trace the wires back from there and I think there might be 2 fuses.

Mine stopped working in the Kimberley. I managed to get a hand drawn circuit diagram off someone on this forum and I found that the black control box had arced out and burnt some wires. I had to open the box and then solder a wire onto each plug terminal, with a crimp connector at the end of each. Then I cut the plug on the loom which had also been damaged by arcing and crimped connectors onto that. I was limited for what materials were at hand and I only had blue wire, so not even any color coding. Anyway, that fixed it.

Mine was serviced many years ago and still works very well. Most people complain about how cold it is on the passenger side, and often cover their knees. The unit will cause condensation on the LHS dash and at half throttle blows air at 4 degrees Celsius. So sort it out, because there is potential for really cool air.

Another mod I did to it was run a 6mm wire from battery to the fan that I can quickly un/plug. This bypasses the fan switch, which supplies reduced voltage to the fan as a way of controlling fan speed. Now with the car running, the fan can run on around 14 volts, so it blows that bit harder. I searched for repairable voltage drop (poor connections) before doing this, but the voltage at the switch was the same as at the fan. Having said that, a mates 98 Tdi doesn't have the voltage drop I get through my switch. o measure it before you spend time splicing wires in.

[strangy]

Most likely has loss causing the low pressure switch activation to prevent compressor damage.

With ignition but no engine running you should be able to hear the compressor clutch engage/disengage with aircond on off or thermostat controls.
Bridging the low/high pressure switch wires will quickly indicate if low gas is the symptom.
Then you need to find the leak

[strangy]

Howard, the Defender TD5 ac compressor is the same as the D2.

[travelrover]

Most likely has loss causing the low pressure switch activation to prevent compressor damage.

With ignition but no engine running you should be able to hear the compressor clutch engage/disengage with aircond on off or thermostat controls.
Bridging the low/high pressure switch wires will quickly indicate if low gas is the symptom.
Then you need to find the leak

Thanks strangy

Lots to do tomorrow if the rain clears a bit. (The council graded our road yesterday so that means heavy rain until its all pot-holed and corrugated again!). I know where the leak is on the Tdi. I just need to get it to an A/C service place. But the Td5 has priority as that is my daily drive and the Tdi will have to wait and based on some of the comments above not sure I could afford to have both fixed just now ;-(

[strangy]

Well, at least you’re not in Alice Springs where the weather has been consistently a balmy over 40