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Fri Sep 26, 2008 6:34 pm

I just received my 1981 Gas Caddy a few nights ago and I’m excited. The first night I drove the truck home the fan was working fine. Today while I was cruising during my lunch break I almost overheated because my fan failed to engage. The fan dilemma is that when I was checking the fuse it appears someone has been doing some customer wiring work – the original fan fuse socket was melted and they rigged a new connection to the R WIPER port.
Why do you think my fan just stopped working? What tells the fan to turn on?
Do you think the relay is fried?

Any troubleshooting advice would be greatly appreciated because I’m at a brick wall.

Also, while we are talking about wiring – why would have the previous owner have run a wire from the back of the alternator directly to the battery?

Where is a good place to order a complete wiring harness?

Thank you,
Ryan

Sat Sep 27, 2008 10:36 am

The fan comes on via the thermo-switch at the bottom of the radiator. To test the electrical system, you can unplug it and jumper the wires - I think you just have a single speed switch on yours. The fan should turn on with that jumpered - and depending on how they rigged the wiring, it supposed to come on regardless if you have the ignition key on or not.
The thermoswitch looks like this:

If it doesn't come on with that switch bypassed, then you have other problems. There is a relay on the radiator itself - that can go bad.

Also, if you have functional air conditioning, turning it on immediatlely should kick the cooling fan relay, and thus, the radiator fan on.

You might have to get a new fusebox - those are well known for having issues. But I don't even know if there's one available for a 81 truck. Nor a wiring harness. Sorry... :cry:

Running a wire directly to the battery from the alternator, not uncommon on the A1 engine layout, where the alternator is mounted on rubber bushings. They ground via a strap between the alternator and the mounting bracket but sometimes people want to make a more direct connection. And same for the positive lead - making a direct connection sometimes bypasses issues in the vehicle's wiring.

-Andy

Sat Sep 27, 2008 11:50 am

Would a 1985 Cabby wire harness work for a caddy?

Thu Oct 02, 2008 8:58 am

Too many differences between the 81 and 85.

Most of the wiring will be the same from most MK1 rabbits in the years 81-83. With the addition of a few sensors. The 84 wiring changed due to the new instrument cluster, but it's pretty much a bolt in.
In 85, the wiring drastically changed going to a digifant engine management system. Some of the wiring stayed the same for standard components like wipers, lighting and charging.

Thu Oct 02, 2008 2:20 pm

Digifant, in 1985? Digifant didn't start until 1986 - and that was Vanagon. Californina cars aside, Golf/Jetta didn't get it til 1988. The "cabby" (I don't like cabby and caddy terms, too easy to confuse) - Cabriolet, didn't get Digifant until 1990.

Thu Oct 02, 2008 2:36 pm

Are you totally sure about that? The 1985 Golf GTI had digi, and that's the same motor they put in cabbies.

Thu Oct 02, 2008 2:53 pm

The 1985 Golf GTI had fullly-electronic ignition, knock sensors and a electronic idle speed stabilizer, but it was not digifant! It was still CIS-E, with a mechanical fuel distributor. I remember one such car I used to work on, we nicknamed it "Dameon" because it had electrical problems that were hell-on-earth to diagnose.

Thu Oct 02, 2008 7:58 pm

83_WabbitGTI wrote: Are you totally sure about that? The 1985 Golf GTI had digi, and that's the same motor they put in cabbies.

For North America:
1980 Cabriolets: CIS-Lambda, 1.6L EJ
1981-1983 Cabriolets: CIS-Lambda, 1.7L EN
1984-1989 Cabriolets: CIS-Lambda, 1.8L JH
1990-1993 Cabriolets: Digifant, 1.8L 2H

I'm totally, 100% sure; I'm your resident Cabriolet expert. 8)

Just because the A1 Rabbit switched to the A2 Golf, doesn't mean the Cabriolets did as well. All Cabriolets are A1 chassis cars and do not share the same mechanical nor electrical equipment as the A2 chassis cars. :wink:

As for using the '85 Cabriolet wiring harness as a whole, you can; however, the 1985 German-built Cabriolet will have a different set-up than your American-built 1981 Caddy (if you have re-wiring to do, get yourself a Haynes or Bentley repair manual).

I don't know that your original fuse/relay panel is still available new (most likely not since the ceramic fuse panels went out of style in 1983), but most people upgrade/update their panels to the newer CE1 panel, which is still readily available. Furthermore, as far as I know, there is no relay for the cooling fan for the early water-cooled cars, only a fuse.

Common alternator wiring: one positive wire runs from the battery to the starter, from the starter to the alternator; one ground wire runs from the alternator to chassis ground; one blue exciter wire runs from the alternator to the instrument cluster.

Fri Oct 03, 2008 6:02 am

*Bows head in shame* Yup, I've been proved wrong...LOL Guess the older I get the more I forget. Your absolutely right.

Fri Oct 03, 2008 7:36 am

Had I not been getting ready for work yesterday, I'd have posted this from the Bentley 85-93 Cabriolet/Scirocco manual