I’ve swapped an AC system from my old 1998 NB to my ‘newer’ NB and am ready to try to get the thing to work.
I’ve pressure tested the system with compressed air and it holds well so no leaks.
So before I call out someone to fill the system I would like to try to make sure the rest of the system is working…
So far:
AC system holds pressure
the AC switch lights up! (Small wins)
the AC fan does not start when the AC is turned on. Should this turn on automatically? I’ve tested the connector and there’s 0.14V when the AC switch is on.
So i don’t know how to test the relays or the compressor/it clutch. Any advice on how to do this and what else I need to check?
I can’t speak for the mk2 but I wouldn’t have thought it was that different to a mk1. On the mk1 there is a pressure switch on the high pressure line adjacent to the inlet manifold. If you put a link in this the compressor clutch should activate. I wouldn’t try this unless you have the correct gas in as it has oil in the system and may damage the compressor or seals. The fan comes on at the same time as the compressor clutch, it’s on the same circuit.
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Thanks for the suggestion. Would it be possible to test the action of the clutch with just the ignition on so the compressor doesn’t actually try to pump anything?
Hi Adam,
" Would it be possible to test the action of the clutch with just the ignition " my gut feeling is no as the A/C relay is controled by the PCM. On the MK1 12 volts comes from the battery through the A/C relay to the pressure switch to the A/C clutch. As Robbie says try putting 12 volts on the compressor terminal. Do you know if the A/C relay is energising? If it is there should be 12 volts on one side of the pressure switch. I’ve tryed to look on the Mellens site for the MK2 diagrams but it seems to be down at the moment.
When i’ve done this before ( on different vehicle ) it was just a case of removing the two pin connector from the pressure switch and taping a paper clip between the connector contacts. If single pole connector it maybe that it just needs grounding to energise with ignition on. Those clutch mechs are a robust piece of kit.
mk375, I connected the single spade connector to the +ve of a separate 12V battery and had a jump lead go from the case of the compressor to the -ve. I measured 12V but there was no indication that anything happened.
I think disassembly of the compressor might be in order. I cannot afford a new one!
Used MK3 aircon compressors are available very cheap, so do not waste too much time on it.
I sold a cleaned guaranteed one recently for about £35 and there are lots around cheaper that that delivered.
As others have said the clutch actuation electro magnet is not something that tends to go wrong but if it has, it has. Make sure you have an effective earth on the pump and that there is continuity in the live cable.
The pressure switch on the early Eunos very easy to bypass. Not sure about the MK3 but imagine it is similar. From memory I used a bent out paperclip to test our Eunos too.
Hi Rhino666, thanks for the response. The problem i’m having is with a 1998 NB AC pump. Model number 442100-0221. I’ve had it on the bench and checked continuity for the earth and she doesn’t budge. I’m able to read 12V between the compressor housing (bolts in fact) and the battery +ve so there is a circuit.
There is a used on on auto link and I’ve enquired about that, but I have also found this one from China:
It’s a slightly different model number (442100-0223 vs 442100-0221), but looks the same and is advertised for the same vintage. Also it’s new and not very expensive… I have enquired to see if it is equivalent and may consider taking a punt on it given a new OEM one is £800+!
Sorry Had MK3 in my mind. Lots of enquiries about aircon at the moment as people hope to be out an about in the heat of summer.
I have 2 x 442100-0221 and 1 x 442100-0224. I think the 224 may have come off a 2002 MK2.5 Montana as a few fitted to them.
That new one would fit but the connectors look a little odd. 223 would be a correct part number but no doubt just hijacked anyway:-)
Handled dozens of pumps mostly off MK1 - MK2.5 and never had one with a goosed electro magnet.
Just re-read your first post. Is this to fit to a 2004 car? I ask because someone asking me questions on ebay(MX5Bitz) and situation strikingly similar to yours.
Given the price of Autolinks pump, I would probably buy that but it would be bought at your risk as no guarantee. Difficult with these nowdays as you probably will not know if there is a problem until the system has been charged.
I have 2 1998 mk2’s! One a jap import V-Special with plenty of good stuff, rust, dents and 130k on the clock. The other is a UK poverty spec I bought with 34k on the clock and had been garaged all its life. That now has most of the goodies from the other one on it. I was in several minds whether to swap over the AC as it had never worked on the jap one since I had it… but I have sweltered too many times gasping for AC, so if I can get it working for a few hundred notes, i’ll give it a shot!
The compressed air I put in the system yesterday held perfectly over the course of a couple of hours I was monitoring it for. But by today had dropped a fair bit. Given the compressor is not working, hopefully replacing that and then getting someone into regas will get it sorted…
I’ll take a closer look at the connector from the compressor I have. But splicing the old connector onto the new unit doesn’t sound like much of a hardship… We’ll see what the manufacturer says about it.
I’ve contacted the Chinese company and it looks like they have the matching part number. You ar correct about the connections on the 422100-0223 - there’s an additional wire from the side going to the top.
The one shown looks very very similar - i cannot discern a difference other than the labels.
The price of the new one is USD190 including USD88 for shipping. Works out around £150 total.
Compared to £50 for used or £800 oem, I think i’d rather the new part as then I can be reasonably confident that any problems will be elsewhere… also the confidence that the part will be capable of somewhere close to 100% function!
OK, so it took a couple of weeks for the Chinese company to build the compressor but it was shipped on a Thursday and arrived the following Monday. There was an additional £18 fee for import - £12 of which is the FEDEX admin charge!!! Feckers.
So total cost of the compressor is £182 or there abouts. It cost me £50 off eBay for a new pipe (the original had a big corrosion crack in a tight bend.
Today the car passed its MOT and the aircon system was charged for £70+vat and is delivering reasonably cold air for the first time so I’m stoked.
Fingers crossed that it holds charge and will be a positive addition.
