Air Con system. - Page 2

Uncle Dean · 5th October 2020, 17:02

I was sure I read somewhere to swap them over as a check.... oh well.

thanks Simon for the advice. I was hoping that his "green dial" was reliable..... ha ha.

If I apply 12v to the red wire going to the compressor will that activate the clutch ?
If it does will I see any result or is it all internal?

thanks again to all who have responded with advice, I am also a member of the P6 forum and again a wealth of great knowledge.

Dean

SD1too · 5th October 2020, 18:40

Quote:

Originally Posted by Uncle Dean

I was sure I read somewhere to swap them over as a check.... oh well.

You probably did Dean. You're not the only one to have made that reasonable assumption. Unfortunately it's not the correct one!

Quote:

Originally Posted by Uncle Dean

If I apply 12v to the red wire going to the compressor will that activate the clutch ?

Yes but that would be most unwise.

The reason for your compressor clutch not engaging is that the refrigerant pressure is below the minimum threshold. The trinary switch detects this and cuts the supply to the compressor clutch relay. The solution is not to force the compressor to engage but to correct the problem at source by having the system recharged with refrigerant.

Simon

Uncle Dean · 8th October 2020, 14:39

Yes but that would be most unwise.

The reason for your compressor clutch not engaging is that the refrigerant pressure is below the minimum threshold. The trinary switch detects this and cuts the supply to the compressor clutch relay. The solution is not to force the compressor to engage but to correct the problem at source by having the system recharged with refrigerant.

Hi Simon,

I was not planning on driving with
Trinary switch bypassed just to use the 12v feed as a diagnostic tool to check the compressor before filling.

Fan sorted and works lovely.
Decided to only take the Front grille off rather than the whole bonnet assy. Fun job, good job I am used to working in confined spaces

I must make a mental note to tap the holes on the resistor before soldering next time.

Uncle Dean · 8th October 2020, 15:45

To Simon.

He nailed the problems from the start.
1. Resistor...... replaced and working.
2. Used the Trinary bypass diag from another post and compressor running.... either faulty switch (unlikely) or needs refill despite Mr.Halfords green dial.

advice from a newbie..... if you ask the forum for advice, then heed it when it comes.

cheers.

COLVERT · 8th October 2020, 19:22

Quote:

Originally Posted by Uncle Dean

To Simon.

He nailed the problems from the start.
1. Resistor...... replaced and working.
2. Used the Trinary bypass diag from another post and compressor running.... either faulty switch (unlikely) or needs refill despite Mr.Halfords green dial.

advice from a newbie..... if you ask the forum for advice, then heed it when it comes.

cheers.

You also nailed the problem by using this all knowing forum.---

SD1too · 9th October 2020, 07:49

Hello Uncle Dean,

Thank you very much for your kind appreciation. To be fair, it was other members who advised you about the resistor. You're quite right though to say that it's very unlikely that your trinary switch is faulty. For air conditioning it's best to give Halfords and the other fast-fit boys a wide berth and seek an independent mobile specialist who really knows what he's doing!

Simon

Pueblo_Boy · 10th October 2020, 16:30

I was going to have mine checked out by a mobile guy from Edinburgh - 0775487395. No idea if he's any good, as I didn't go ahead, but his prices were very reasonable.

As for travelling down to Spain, I did that last October

Took the overnight ferry to Dieppe, saves an overnight stay in France and some miles

If you're going down to the Costa del Sol, there's a scrapyard in Malaga with an MG ZT in good condition - exhaust looked like new! But it's missing its intercooler

9th October 2020, 07:49	#16
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,374 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Hello Uncle Dean, Thank you very much for your kind appreciation. To be fair, it was other members who advised you about the resistor. You're quite right though to say that it's very unlikely that your trinary switch is faulty. For air conditioning it's best to give Halfords and the other fast-fit boys a wide berth and seek an independent mobile specialist who really knows what he's doing! Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

10th October 2020, 16:30	#17
Pueblo_Boy Loves to post Rover 75 Tourer Join Date: Nov 2018 Location: Sauchie Posts: 370 Thanks: 66 Thanked 56 Times in 36 Posts	I was going to have mine checked out by a mobile guy from Edinburgh - 0775487395. No idea if he's any good, as I didn't go ahead, but his prices were very reasonable. As for travelling down to Spain, I did that last October Took the overnight ferry to Dieppe, saves an overnight stay in France and some miles If you're going down to the Costa del Sol, there's a scrapyard in Malaga with an MG ZT in good condition - exhaust looked like new! But it's missing its intercooler __________________ 24,658th 75 Tourer made, out of 27,407 136th Tourer CDT Contemporary SE (135hp) out of 364 194th 75 Tourer in Firefrost Red out of 518 Firefrost Red 75 Tourers Interior Trim Sports PPH Black, but now with real walnut wooden trim! One of only 20 on the road!

5th October 2020, 17:02	#11
Uncle Dean Regular poster Rover 75 Tourer Join Date: Aug 2020 Location: Edinburgh Posts: 43 Thanks: 15 Thanked 24 Times in 11 Posts	I was sure I read somewhere to swap them over as a check.... oh well. thanks Simon for the advice. I was hoping that his "green dial" was reliable..... ha ha. If I apply 12v to the red wire going to the compressor will that activate the clutch ? If it does will I see any result or is it all internal? thanks again to all who have responded with advice, I am also a member of the P6 forum and again a wealth of great knowledge. Dean

8th October 2020, 14:39	#13
Uncle Dean Regular poster Rover 75 Tourer Join Date: Aug 2020 Location: Edinburgh Posts: 43 Thanks: 15 Thanked 24 Times in 11 Posts	Yes but that would be most unwise. The reason for your compressor clutch not engaging is that the refrigerant pressure is below the minimum threshold. The trinary switch detects this and cuts the supply to the compressor clutch relay. The solution is not to force the compressor to engage but to correct the problem at source by having the system recharged with refrigerant. Hi Simon, I was not planning on driving with Trinary switch bypassed just to use the 12v feed as a diagnostic tool to check the compressor before filling. Fan sorted and works lovely. Decided to only take the Front grille off rather than the whole bonnet assy. Fun job, good job I am used to working in confined spaces I must make a mental note to tap the holes on the resistor before soldering next time.

8th October 2020, 15:45	#14
Uncle Dean Regular poster Rover 75 Tourer Join Date: Aug 2020 Location: Edinburgh Posts: 43 Thanks: 15 Thanked 24 Times in 11 Posts	To Simon. He nailed the problems from the start. 1. Resistor...... replaced and working. 2. Used the Trinary bypass diag from another post and compressor running.... either faulty switch (unlikely) or needs refill despite Mr.Halfords green dial. advice from a newbie..... if you ask the forum for advice, then heed it when it comes. cheers.