So I've now completed installing all the hoses. Just the wiring to do. @rubjonny I'm afraid that when I compared the wires I'd stripped out of the engine bay loom, with the MK3 aircon wiring diagrams you shared I couldn't match them I'm just after a manual system, ie press aircon button and the aircon works. I'll faff with the vacuum recirculating system later. From what I understand this is how the aircon should work - Listed as a sanity check of my understanding !: The Compressor will circulate the refrigerant round the sealed loop but will need the fan to cut in to convert the liquid to a gas to cool the air passing the evaporator. The aircon will not work if there is insufficient pressure in the system - there is only one pressure sensor module on the MK3 which is connected to the dryer. The aircon won't work if the outside temperature is low, hence it needs to be linked into the outside temp sensor ? This is the wiring I've stripped out. I just need a "Noddy" guide as to how I connect it all up! https://ibb.co/qMs4YmR Unfortunately not all the connectors were labelled-up.
How about this? I used it to get my wiring right. From here https://www.golfgtiforum.co.uk/index.php?topic=74087.0
I think you need to plumb in: 1. Low pressure switch to cut compressor when not enough refrigerant. 2. High pressure switch to cut the compressor when the pressure is too high A decent a/c installer will be able to fit those into the "charged" system pipe. The fan comes on to not only aid the cooling of the refrigerant through the condensor but to cool the engine coolant as the engine works harder with the a/c on. My factory install has a temperature diode fitted to the evaporator to switch off if the temperature gets too low and risks freezing the system. It does not have an external temperature sender at all and is not connected to the MFA outside sensor at all. I guess you could get away without such a diode in a temperate climate or simply not switch the a/c button in winter. Hope this helps.
so: white connector - F38: outside air temp, sits in scuttle next to ecu black plug inline with above - F163: coolant temp sensor, on abf its in side coolant flange (can bridge pins to bypass) black connector, brown/green - N63: recirculation valve 4 pin - F129: pressure switch green connector - T2d: goes to the 'AC' and 'recirc' switches inside car red on fan switch is permanent live, join that to the red on the 2 pin plug near mk2 passenger headlight. black/yellow on pressure switch goes to ignition live, the chunky black with ring terminal connected to all the brown/greens goes to battery or chassis earth. rest of the cut wires all go to the mk3 fan control module and are your triggers for fast fan speed, a/c switch on and ac disable. If you dont want that, you'll have to substitute relays. thats all you find inside the MK3 FCM theres no complex electronics in it really. use my g3manualac.pdf wiring diagram, its all in there pretty simple even the colours match
if you want to convert it to use simple relays the corpgaircon.pdf might help its the same wiring as the mk2 golf and uses the '13' ac relay on fusebox which has 3 internal relay switches for fan, aircon and fresh air blower
tbh mk3 is simpler imo, a little less wiring and the wiring is pretty much all in the engine bay. but there isnt a great deal to it, the 13 relay on fusebox is equivalent to the mk3 fan control module in the bay
Thanks John, I took another look at the wires I untangled and I didn't add the Ambient Temp Switch connection to my diagram which in my case has Red/White - Brown/White. I checked to see if the sensor (VDO 357919379A) fitted in the white connector above (perhaps previous owner had put in the wrong connector?) but it doesn't, it has 2 guides not 1 on the sensor. EDIT found in the box of goodies 357919506A 2 connectors. Which FCM model do I need?? A quick look on evilbay shows 357919506 suffix of A, D etc. Assume the one with 2 connectors?
@rubjonny if course it is.. How silly of me not to know what I'm doing. So I've had another trawl on evilbay for a pic and it looks identical in shape to the blue and black sensors that fit into the engine flange. I will have to have another look in the box of bits I got to see if I have one. Then think what I can mount/tie wrap it to. At least that mystery is sorted and explains why I couldn't find those colour wires on the diagram!
I'm back......! So I went in search of the missing parts I didn't realise I was missing: MK3 FCM with expansion bottle mount, ambient air temp sensor and the Aircon/Recirc switch connector with wiring. Fortunately a guy on FB had the bits. He sent me the FCM, both connectors with a length of wire (Stupidly I'd tried to remove the pins/cut the wires short...PITA) and some duplicates of what I already had. So now I think I have everything...... So using the "painting by numbers" approach to wiring I'm matching the FCM connectors to the full aircon wiring diagram above and there are some discrepancies: FCM connector 3A0 973 715 1 Blank 2 Brown/Green - (Red/Yellow on the diagram) 3 Green/Grey - (Green on the diagram) 4 Brown - (Not on the diagram) 5 Blank 6 Brown/Green 7 Red/Yellow 8 Green 9 Black/Yellow 10 Green Black I'm going to connect everything up "loosely" so I can test everything works and work out how the MK3 loom is going to route round the engine bay before I splice the cut wires and solder then wrap with tape.
confirm your plug vs the diagram on the side of the FCM, vs this list: T10: (pin number, circuit ID) 1 - WP - red/blk - coolant pump (6cyl) 2 - P - yel/red - a/c pressure switch, too high(?) 3 - T1 - gry/grn - a/c switched on & all switches 'OK' 4 - T - brn/red - coolant pump thermoswitch (6cyl) rad fan after-run switch (4 cyl) 5 - T3 - blk/wht - fan speed 3 trigger (6cyl) 6 - 31 - brn/grn - earth 7 - T2 - red/yel - fan speed 2 trigger 8 - T4 - grn/red - connected to T10a/3 (4cyl), a/c relay output (ecu sensors 'OK', 6cyl) 9 - X - blk/red - x-relay live 10 - MK - grn/blk - to a/c compressor
This is where I'm confused John... So these are the FCM connectors wired into a temp jointing block so I can test/suss out the routing before permanently joining to the aircon loom. FCM connector 3A0 973 715 was from a MK3 with aircon. Pin 1 & 5 don't have any wires installed. Looking at the original connector I tried to remove the pins Pin 8 is Green/Grey (not Green) but otherwise they are exactly the same.
1 & 5 are only for the VR6, so if the donor was an 8v thats to be expected. wire colours can also vary depending on age/donor/market so I wouldnt worry toooo much, just confirm the wire goes where you think it goes before powering up
Howdy, I've reread this discussion a few times, and I hope I kinda know what I'm saying USA - LHD 86' MK2 Golf 1.6na w/AC wo/PS This was bought to eventually become my new daily driver. I plan to convert to an ALH TDI engine, and I recently parted everything from a 1998 MK3 Jetta TDI (AHU engine died). To make the MK3 TDI Rad-fan assembly fit the MK2, I bought Fabless front cross member and upper radiator mount supprots, as Passat B3/B4's are getting harder to obtain in the states. The main reason for the donor MK3 was the subframe and suspension to the get the newer A/C mounts, but I kept EVERYTHING from the car. Least till after the conversion is done In this adventure, I'm ditching the Murrican' electrical system, and fitting a 91' jetta (ecodiesel engine harness side) and 92' gasser jetta everything else CE2 harnesses, I even have a GTD (as the MK3) diesel cluster to use. So, plan is to ripe out all the OE harnesses and install the updated CE2 harnesses in the MK2 Golf. Because, the MK2 Golf 1.6na has A/C it's a little more unique situation than some of you have had finding it for non/AC cars. In that regard, I'm fortunate. My goal for this daily is a good method to implement the A/C which makes the most sense. I have the ALH engine side harness for the ALH swap, I also have the complete MK3 TDI AHU (engine and car) harness with the FCM module for the rad-fan assembly, as the AC hardlines; everything from the car was kept. Knowing the above information, here are my questions: 1.) From the reading, the MK2 A/C system seems overly complex compared to the MK3 & MK4 systems especially once you've converted to CE2. From that reading it seems if I want to have recirculation with the A/C I have to upgrade my MK2 HVAC assembly. Am I better off replacing the HVAC assembly (whole thing AC & Heater core) of the MK3 to the MK2? If Yes, I've heard that the LHD assembly would fit right up, and I've read that the bulkhead needs modification, is there any actual concensus on the N/A side of the pond yet? Looking at the MK2 (nothing removed yet), and the disassembled MK3 they seem very close to location. 2.) Cockpit (inside car) controlling of the A/C. This is where things get a lil fuzzy for me. This ultimately is decided on #1's which HVAC assembly you use correct? And the decision of #1 is based around ReCirculation which I want to reduce the wear on the compressor. 2a) If I use the slider controls (MK2 factory) I can use a micro-switch in the slider housing to activate the recirculation function once at a certain range of A/C needed. 2b) If I use the round controls (MK3 factory) which I assume would fit in the same spot the old A/C controls did--if not please state something someone. If both controls can be fitted into the MK2 dash, is one control method better than the other? Such as, do the MK2 tracks get dirty and jammed compared to the dials? etc. Just thinking which would be better lasting down the road over time, or both work equally well? 3.) FCM, If going the MK3 dual rad fan setup and A/C, the FCM is going to be part of this equation. As I'm using an ALH engine and have that side of a harness to the MK4 FCM, am I better off using a MK4 FCM or splice in the MK3 FCM plugs and remap the wires here? 4.) A/C Low & High lines. What's been people's luck here? 4a.) Retrofitting the existing MK2 lines and finding a MK4 compressor line adaptor? 4b.) Retrofitting the MK3 lines and finding a MK4 compressor line adaptor? 4c.) Having new Low and High lines created? I think these are the only real A/C conversion related thoughts I'm still ironing out if anyone could shime some expertise on. Thanks!
