TheSamba.com :: View topic - Electrical gurus . . . Need a little help.

Thu Dec 04, 2008 3:08 pm

I need to put a switch on the dash that will engage the A/C compressor. The PO pulled out all the A/C stuff incl. dash switches (but wire bundles are still there). I can't make any sense of the electrical schematics in the Bently no matter how hard I try.

What I need to know is which wires at the dash will engage the compressor clutch. I'm guessing one in the existing wire bundle that used to go to the AC controls will do it but I have no idea which one(s). Or maybe there is a spot on the power block/fuse board that will do it.

Anyone have any ideas.....

Thanks in advance.

Thu Dec 04, 2008 5:01 pm

If you want a better schematic get it from my public folder:
http://homepage.mac.com/WebObjects/FileSharing.woa...mp;lang=en
Download:
Vanagon Wiring Diagram.pdf

See if these help a bit:

Thu Dec 04, 2008 6:03 pm

the a/c fan switch has four slections (1234) the you must turn the temperature control (the one with a snow flake on it)on to engage the a/c clutch, compressor and cooling control, then the fan switch will work, the power is fed from the temperature dial to the fan switch(i changed this) if the temp sw is turn on just a little this will allow the radiator fan to run if the ignition sw is off.

personally i changed the wiring so i could turn the fan on anytime to circulate the air in the van. just ran the power to the fan selector switch.
the power for the temp controls and fan will have power even if the ignition sw is off this is so the radiator fan control can work when the ignition switch if off. the a/c blower is a strong dual motor fan and works great as a fan to circulate air in the van.

Sat Dec 06, 2008 7:01 pm

Hey Dog, thanks for the schematic. Thing is it's all greek to me. Looks like the A/C Clutch is on wire 15. I have no idea what that means. Sorry to be such a bonehead but I seem to have a learning block when it comes to schematics.

Does anyone know which wire in the dash control bundle wire 15 is? I don't have the knobs anymore so I'm not even sure which plug would have gone to the temp selector vs. the fan speed selector.

:?: :?

Tue Dec 09, 2008 8:00 am

All of the numbers on the chart correspond with numbers on the plugs themselves. You may have to get a magnifying glass out but they are there. Also the wiring chart states the colors of the wires as well so you can figure it out that way. I would warn you that what you are trying to do is a very bad idea. What you should do is to get all of the proper used parts from a donor van and put this system back together properly. I really don't think it is going to work right by "Jimmy-rigging" the system. If you get the A/C clutch to engage, then what? You still have to get the fan speeds to work. What about the clutch cut-out when you are up to temp? You need the clutch to kick off when your evaporator temp is cool enough. If it keeps going no matter what then you could get evaporator icing up and that can cause the whole system to fail or at least stop working. Also you need to have the front radiator fan coming on when the A/C system is working. If not your system pressure will increase until your high side line or your drier explodes like a bomb. If the clutch runs when you are too low on refrigerant then your compressor can lock up, sling off the belt taking the water pump belt with it, and your engine instantly overheats, killing it too. I have seen this before.

It should cost too much money to get this properly repaired at a shop that knows electric. If all you are missing is the front switches then just buy them from someone who is parting out a van and then have someone troubleshoot the system for you (I am sure there are other problems that's why they took out the switches) and you can have a nice working system without these gremlins popping up every other week.

Just my advice but I have spent the last ten years working on Vanagon A/C systems so I guess I know a little bit about it. If you find you need any parts please consider us.

Tue Dec 09, 2008 12:30 pm

sc-surfer wrote: Hey Dog, thanks for the schematic. Thing is it's all greek to me. Looks like the A/C Clutch is on wire 15. I have no idea what that means. Sorry to be such a bonehead but I seem to have a learning block when it comes to schematics.

I know Dogpilot sent a different diagram, but in the Bentley diagrams the number at the bottom refers to the current track. In a very simplistic way, in my mind, I look at current tracks this way. The line along the bottom of the page is ground and the lines along the top are + or -

Pretty sure all this stuff is explained in Bentley.

One tip.

And this had me confused for a while til' someone else explained it.

When the schematic shows a wire from a component "stopping" at a boxed number, we know to look to the corresponding current track to see where the wire continues. i.e. P 97.116 current track 151. The 1.5 brown wire from the "warm air blwr" "stops" at boxed "69". BUT. In looking at current track 69, we need to look for a boxed "151" to see where the wire in question continues. It should be the same colour in the diagram.

Cheers,

Neil.

Tue Dec 09, 2008 1:08 pm

I mean no disrespect, but all I can say is if you want to take on electrical repairs or alterations, you have to learn to read the schematics. Other than the most obvious, simple problems, anyone attempting to help you will have to refer to the diagram. If you can't read it, they can't help. If you won't take the time to learn (no one was born knowing it; any one of use who helps with these things took lots of our own time learning first), then take your van to the shop. I don't mean to be harsh but I think it's asking a bit much of helpful but unpaid people to talk you thru a problem when you have no common referents.

A seminar of sorts on reading the diagrams is something I've thought this site could use for a long time. But hardly anyone refers to the stickies first, so the questions will still go up on the forum anyway, so forgive me if I'm not the first one to volunteer.

Tue Dec 09, 2008 2:37 pm

The days of the color wiring diagrams laid over a silouette of the vehicle are gone. I think the last year for that type of diagram was 1971. Cars have much more electronics than days gone by. All the manufacturers have adopted ways of viewing sections of a electrical system. The AC circuit is a little complicated to cut your teeth on. Get a Bentley manual. They have a tutorial how to use the diagrams. I actually like the way VW does it. Some color codes don't make sense, SW is black. Etc. Luckily VW does not splice into wires for power usually. Everything has a home run back to a relay, switch or fuse box. I would pick a simple circuit like the dome light or horn and see how they are diagrammed. Then move on to the more complicated circuits like rear wipers, emergency flashers and in your case the AC. I can tell you a toggle switch alone on the compressor will eventually cause the evaporator to freeze up. You need a thermostat in the circuit to shut the compressor off before freeze up. Regards

Tue Dec 09, 2008 2:41 pm

There is a sectional guide to the electrical drawings in the Bently. I even had to read that section, even though I'm an electronics engineer by training. Read it!

IMHO, no-one should work on their vanagon electrical (and most other systems) without a Bently service manual. There are too many peculiarities and differences for different model years to get away with not using one. Buy, beg or borrow one.

Tue Dec 09, 2008 3:36 pm

The German word for black starts with SW so it makes sense to German speakers. Most Vanagon Bentley diagrams use BK for black but there are a few where the translation was a little messed up and German color names were left.

Mark

rsxsr wrote: ...............I actually like the way VW does it. Some color codes don't make sense, SW is black.

Tue Dec 09, 2008 4:01 pm

The current track system actually is easy to learn and helps out a lot more than the old wiring diagrams. If someone is fresh and learns from the start how to use the current track diagram, they can figure out the problem faster.

here is a link to explain it;

http://www.bentleypublishers.com/images/tech/vw/vw.wiring.diagram.pdf

Tue Dec 09, 2008 7:10 pm

I agree, the current track type diagram is the most comprehensive and understandable way to map out an electric system I've seen in any manual. The method is very data-rich; there is practically nothing you can't locate. It seems a little strange, when I saw my first one I thought it was idiotic, because I had to learn the method to understand it. But once I did, I wish every car manual did wiring this way.

The wiring colors are of course German, so they make absolutely perfect sense, although the edition I have has the colors in English.

Tue Dec 09, 2008 8:54 pm

tencentlife wrote: I agree, the current track type diagram is the most comprehensive and understandable way to map out an electric system I've seen in any manual. The method is very data-rich; there is practically nothing you can't locate. It seems a little strange, when I saw my first one I thought it was idiotic, because I had to learn the method to understand it. But once I did, I wish every car manual did wiring this way.

The wiring colors are of course German, so they make absolutely perfect sense, although the edition I have has the colors in English.

I can't agree! Having done the Subaru wiring this summer, meaning dealing with and relocating massive numbers of wires, I found the Subaru diagrams easier to read than the VW, even though I've spent alot of time with the Vanagon wiring and there is much more Subaru wiring to deal with, as the computer is more sophisticated.

The annoying thing with the Bently wiring diagrams is running all the grounds to a line running on the bottom of each page, and all the ignition, 12V, and other lines up at the top. Standard practice is to use a ground and +12V symbol wherever you need to connect and use a reference number when the signal goes off the page. That makes the diagrams easier to read. (Less lines running up and down on the page). In the case of the vanagon wiring, it'd remove over 50% of the lines on the pages, as well as save on ink and paper.

Of course, the Germans had a strict sense of richtig and verboten, which likely got in the way of what's easy and makes sense.