Flash Gordon is alive!

[Jumbungla]

Made some good progress on the van over the last few days! Nearly have working AC in the van now.

Started by marking up and cutting out the bulkhead to fit the AC plate.















Worked nicely I think, and the AC heater/control box in the cab fits nicely through the bulkhead.

Then got the new belt fitted, which I measured out to be 1215mm. And this was perfect! Only just long enough to get it over the pulleys, leaving me more than enough space on the "manual" tensioner pulley to get the belt tight.



Shit bit is this is when I realised the compressor was wrong. I thought the fact it was an 8 rib pulley on the compressor wouldn't be a problem with my 6 rib belt. But with this and the fact the alt pulley is slightly wonky due to the mount, the belt wanted to jump off on startup. This resulted in me mounting an old Seat Leon cam sprocket on the tensioner as a makeshift barrier to stop it jumping off. Worked-ish, and I only lost one rib, but meant I could get it up to the local indie for the pre-mot.

But i realised I needed to get a new compressor as the hose connectors on the compressor are the screw type, and the proper VW AC hoses are a compression flange type fitting. Got a new compressor turning up in a couple of days.

Pre-mot looks good. Small patch on the inner sill behind the exhaust shield needs welding. And outer cv boot has a pinhole in. Easy stuff.

Back to the AC. Then decided to tackle the electrics. Which was pleasantly easy.

Didn't look it to start off with, with this rats nest of cables.



But i just took back the existing heating loom, and unplugged cables, and plugged in the new cables as I went along.

Did the same with the fuse box. Removed connectors, untangled them, and plugged them back in neatly. Looks much better now.

Then fitted the new coolant pipes and rad with the condenser rad included.

Pretty easy again. Just needed to install this extra sensor inline in my existing coolant pipework.



Everything is in now and the whole heating/cooling system works. Much better than the old busted unit I had in.

Next steps are to fit the new compressor, fit a new belt, connect the AC hoses. Fit new receiver drier unit. Then gas up the system, and see if I get sweet sweet cool air.

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[Jumbungla]

It's taken me a while. But a new compressor and new alternator, and lots of fettling later, I've finally got the Aux belt running nice and straight and not jumping off. Left the sprocket guard on anyway, quite like it to be honest.





Had to cut 4mm off the side of the mount as the new compressor stuck out a little bit further than the old one.



Then had a problem getting the belt tight enough with the crappy manual tensioner pulley, even using push out clamps braced against the engine mount to push against the pulley and then tightening the bolt, it would just slip and loosen the belt when running the engine.

So I got the tensioner in the right place and drilled and tapped a couple of 5mm points, to pin the tensioner in the right position once tight enough.



Works fine, but I'm ultimately going to fit the proper tensioner. Just need to find one that's not crazy expensive.



Then got everything connected AC wise. New receiver drier, all new seals.





Then set about learning about gassing up AC systems. Already had the vacuum pump, and the manifold gauges weren't expensive.

Vacuumed the system and left it, and it held full vacuum for 24 hours, so a nice fully sealed system.



Put 900g of refrigerant in, but I've got a problem somewhere as the compressor won't kick in. I'm pretty sure it's an electrical problem as the compressor is new.

New AC pressure switch as well, which stops the compressor turning if there isn't any gas in the system.

Urgh, annoying, but I'll go around and check voltages on pins of the sensors and sensor wiring.

But the AC light doesn't come on when pressed in the cab. Which I've read on the T4 means the AC system isn't happy somewhere with something electrical, so won't turn the compressor on.



Oh well, nearly there! Anyone got any suggestions of things to check on the AC electrical system?

Also, how many t4s out there have AC? There isn't a lot of discussion online about it, which makes me think it's not that common.

Oh, and also fitted a nice new resistor mount bracket. Should last a few years.



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[Activ8]

Random thoughts J..... Is there an ECU pprogram switch for AC? .... Does it not raise the revs and therefor manage the engines status when on? Can you connect to the AC system via VCDS?

[Jumbungla]

Nah its an AC system out of a 1.9td, so all "dumb" electronics. Just voltages and switches and relays.

Although one thing occurred to me, I haven't "added" a fuse to the system, but all my fuse slots are filled.

The blowers and recirculate function work fine.

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[arfur fox-acre]

I can't help with mechanical knowledge or anything like that but I have a 2.5 acv which has Aircon if you need any photos etc.

[Jumbungla]

I can't help with mechanical knowledge or anything like that but I have a 2.5 acv which has Aircon if you need any photos etc.

Ah great, cheers arf.

A photo of your relays would be really useful I think. I've only got the one for air con, and I'm starting to think that might be the problem. More likely the wiring to the relay.

Here's mine.



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[Activ8]

Clearly couldn't of worked in a 1.9 as the hoses in the supplied parts from the "2nd hand working" kit were mismatched iirc?

[Jumbungla]

Yeah you're right Rob. I don't see how it could have worked as the pipes were flange fitting, and the compressor was screw fitting. So something doesn't add up. But all the looms have plugged in fine, with nothing left over haha. All sensors have corresponding plugs. From looking at it, everything is there and matches the Haynes 1996 air con circuit diagram.



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[Activ8]

So how do you test the sensors, flap positions, operating pressures etc.

Looked in my 1991-1996 VAG manual and it's showing a diag port into the controls?????

[Jumbungla]

I've only tested the ac pressure sensor properly so far. (lucky I ordered 2) but the one out of the van has all switches open. The one on the van connected to the pressure has one switch closed, the one shown closed on the electrical diagram.

I've tested the thermo cut off switch I put in line in the coolant pipe. But the van wasn't up to temp. But it was still one switch closed and one open as shown on the electrical diagram.

I've checked at my relay board, and getting 12v at pins 6 and 8 under the AC relay, as per electrical diagram.

No diagnostic I can see on my electrical diagram? Odd. What electrical diagrams have you got Rob? Cheers!

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[Activ8]

Only got the VAG 1991-1996 manual bud plus what's on ETKA , which maybe zip but haven't looked tbh.

Just looking to see if I could help bud. Clues in the diagnostics.

[arfur fox-acre]

Ah great, cheers arf.

A photo of your relays would be really useful I think. I've only got the one for air con, and I'm starting to think that might be the problem. More likely the wiring to the relay.

Here's mine.



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Not sure if these really are useful. Not easy taking pictures in a dark underground garage, holding another phone as a torch. To make it even better somebody has bolted. A piece of steel plate across the front, non idea why.
For what it's worth, I have two airbags so they may have relays etc, maybe.

Let me know if you need more or have any questions that I may be able to answer.

[Jumbungla]

Not sure if these really are useful. Not easy taking pictures in a dark underground garage, holding another phone as a torch. To make it even better somebody has bolted. A piece of steel plate across the front, non idea why.
For what it's worth, I have two airbags so they may have relays etc, maybe.

Let me know if you need more or have any questions that I may be able to answer.

Ah no that is really useful, thanks arf. There are relays that are shown on the electrical diagram that I couldn't account for, but good to know I'm not missing any in the relay board. They must be built into the blower unit or something? And of course there are the rad fan relays in the engine bay.

Is the top left relay in your set a 140 like mine?

Looks like the only extras on yours are fog lamp relay and engine control (which i assume is because yours is a posh ecu engine)

Thanks arf, appreciate the effort!

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[arfur fox-acre]

Ah no that is really useful, thanks arf. There are relays that are shown on the electrical diagram that I couldn't account for, but good to know I'm not missing any in the relay board. They must be built into the blower unit or something? And of course there are the rad fan relays in the engine bay.

Is the top left relay in your set a 140 like mine?

Looks like the only extras on yours are fog lamp relay and engine control (which i assume is because yours is a posh ecu engine)

Thanks arf, appreciate the effort!

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I shall check tomorrow for you.
Yep, I forgot about the foglights. They probably have a relay too.

[Jumbungla]

Cheers Rob, appreciate the help! I've looked on 7zap but not much joy regarding the loom and thermo switch detail.

Is there any chance you could share the vag manual? Would really like to look through another set of wiring diagrams that isn't Haynes. Unless they are already uploaded in the file section? I'll check now!

There are some odd things on the Haynes diagram that don't fully make sense, I think they are just misprints, but want to double check.

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