S60 2002 A/C Magnetic Clutch Fix (instead of 'bread clip fix')

[coflynn]

My A/C has been dead for a while, and it was clearly the gap problem. I don't use the A/C enough to "properly" fix it, and never had luck getting the breadclip fixes to last very long. I couldn't get zip-ties in as was too lazy to pull back the inner wheel well too.

I finally tried another method to fix it. It's a bit of a hack which can easily burn out the magnetic clutch, but honestly I'm never going to properly fix the A/C, so would rather have done this, and if it breaks again will give up.

I used a DC-DC converter to increase the voltage being fed into the magnetic clutch. This will increase the strength of the electromagnetic pull-in. I used the following specific device: DROK 150W DC Boost Converter on Amazon. It's available on Amazon.ca as well.

If you have time you can order from Aliexpress for $4, but I wanted prime shipping so paid the extra fee. The device isn't really designed for automotive use so it seems likely to burn out from heat. I'd check it occasionally and watch for the capacitors to buldge out, keep an extra 1 or 2 of them on-hand to replace.

Once you've got this, it's a simple process:

• In the front fuse box, find the grey wire. Cut the wire - the part coming from the relay goes to the "IN+", do not connect the "OUT+" yet!
• Connect the ground wire ("IN-") to a grounding point near the fuse box. I couldn't find an easy ground in the box.
• Power up the system, and turn on the A/C. The green light should come on. Measure the output voltage and adjust it down to about 15V.
• Turn everything off, then connect the "OUT+" to the grey wire going out.
• Replace the input fuse on the board with something smaller (default is 15A), I'd go for about 5A-8A and see if it doesn't burn out.

BE CAREFUL WITH VOLTAGE ADJUSTMENT I set mine around 15-16V, which seems to be the level required for my clutch to not drop out once it warms up. This is about 15%-25% higher than normal, meaning you'll get 15-25% more current through the electromagnet, and more heating as well. This may burn out the coil too since it's not designed to run at higher currents. If you set the voltage too high it WILL burn out the electromagnet.

I measured quickly and it seemed the normal current draw on the clutch was about 3A (at regular car voltage).

[abscate]

That's a nice hack but AC in NS?

Maybe in the south lands of PEI ....

[coflynn]

Ha... the 100% humidity days have been the worst for it lately. But I lived 3 years without it as there's normally only about a week you really need it.

On the plus side I'm not too worried if it burns out. So far so good though - no sign of it cutting out!

[polskamafia mjl]

Awesome that this worked! I feel like this was a lot more work than zip ties, though. lol

[coflynn]

I struggled before with the zip-tie fix... could never get them to fit from the top or they kept flying out, so this fix was way easier... 10 mins tops!

Whereas it takes me 15 mins just to get my jack+jackstands setup in the driveway, so if I was trying to go via wheel liner would have been a much longer procedure.

EDIT: Also my background is all electronic stuff, so anything I can fix with electronics vs. a wrench is 'easier' in my book

[mrbrian200]

Once engaged I would think the normal voltage/current should hold the clutch engaged. Higher voltage need only be applied momentarily during initial engagement (I would guess around 100-250ms), then dropped back to normal voltage. With a (somewhat) more complex circuit you should be able to accomplish this with a much lower risk of burning out the electromagnetic coil as damaging the windings would be a function of excessive heat buildup over a more extended time.

[Driver4life05]

Idk if this can be the same problem but what I found out might help. One day the air blew hot. I went and started the recharge process with buying the guage and a couple cans of the green stuff. Filled it up and it came out cold. No biggie. Than I took a look at the measurements again and came to find that I was still under pressure when the clutch compressor engaged. So I bought another can and started to fill it up. After I filled it up, the clutch didn't want to engage anymore. I was confused.

Than after about a day of frustration, I went to the port where I was adding the green stuff in and took a screw driver and pushed on the needle to release air because I thought that maybe it had to much pressure. Well low and behold I let the air out until the green stuff started coming out and walla!! The compressor engaged and blew cold air again in the cabin.

My consensus is that when recharging the system it tends to fill with air and the compressor works off of pressure right? I have no idea what I'm talking about but if it does than I released the pressure build up in the system which released the tension of the plate and clutch in the compressor so it can engage smoothly and stay in gear without friction build up due to pressure from the air build up in the lines.

This might be one reason why the compressor doesn't stay engaged. Have a nice day!

[abscate]

If you overcharge the system will shut off the compressor. The gauges are notoriously inaccurate , as well as the pressure in the system isn't a good spec unless your are at high idle and system equibrated.

If you really know your AC like jimmy you can get this right, for the rest of us the best strategy is recover old Freon , vacuum system, confirm integrity, then add charge by weight to spec. Done.

People who add a " can or two" each summer will have no AC in Hades when they are sent there.

[KyDave]

Has anyone else had success with this? What was your process? BTW I do have experience in electronics and logically it seems it should work.... "Shimming" the clutch voltage versus shimming the mechanical clutch.

But so far I've screwed up my wife's S60 and had some anxious moments today on my son's 2004 S80. Volvos seem extremely sensitive to the interruption of ground connections. (??)

The S60 worked more/less OK at lower temps but would drop out while stationary at stoplights, etc. Working only under the hood I added a ground wire exactly as shown and unplugged the harness connector at the fuse block. I probed the connector, seemingly confirming the resistance of the clutch coil - with the battery connected. I connected the power supply input to the grey clutch input wire and there was a spark. I'm not sure happened, I wasn't trying random connections and I understand how it's supposed to work. The PS let out a puff or smoke and is dead. The engine started OK. But now the AC doesn't engage and there's an "Engine Service Required" message. I was so bummed I haven't checked it further for an open fuse, fried clutch coil, ???

On my sons worn 2004 S80 I was much more careful. I turned off all electrical functions, waited a few minutes, disconnected the battery, set the PS output at 14V while powered by directly by the battery, added the ground wire by removing one of the three "wheelwell" grounds. When I loosened the ground wire screw I think I heard a click in the engine compartment. I reconnected the battery and attached a clip lead to the fuse box "jumper" terminal with a 2K resistor at the PS output just to prove it would work. I turned the key and NOTHING happened! 2-3 more key turns and nothing. Removed clip lead, disconnected battery and waited, removed extra ground lead, reconnected battery and it started. Now I'm afraid to cut the grey clutch wire and try it again.

[abscate]

Ac clutches dissipate a lot of current and heat, you can probably tell I’m not a fan of upping the voltage to raise the field to solve a wear problem. When you take out the fuse , you take out other stuff too.

The wheel and liner take 10 minutes to remove and ease back