1.6 radiator fan

[rabbit82]

I am working through the bugs on this (new to me) 82 rabbit. What I am looking at now is the electric radiator fan. It was running all the time but it quite. The 50amp fuse blew and welded itself to the fuse panel. I was able to get it out and the arc wasn't to bad so it didn't hurt the fuse panel. Anyway, I replaced it and the fan isn't running now like it was. I haven't had it out to get it hot yet since I am in the process of installing new cv joints and it's on stands. I just thought I would get a jump on this next project. What should I check first.

[8v-of-fury]

Install your on circuit. Way easier than diagnosing this BS. lol Not to mention it will cost you like $10 and the wiring can all stay in the engine bay.

There is a little two prong plug on the bottom of the rad, its a thermo switch. Give power to one side of it and then the other side goes to the relay to tell it to turn on. then you bring a constant 12V to the relay driect from the battery, a wire to the fan, two grounds and your solid. Add in two more wires and you can put a dash mounted switch to turn it on whenever you feel like it.

If you need a diagram I can draw one up for you.

[R.O.R-2.0]

Install your on circuit. Way easier than diagnosing this BS. lol Not to mention it will cost you like $10 and the wiring can all stay in the engine bay.

There is a little two prong plug on the bottom of the rad, its a thermo switch. Give power to one side of it and then the other side goes to the relay to tell it to turn on. then you bring a constant 12V to the relay driect from the battery, a wire to the fan, two grounds and your solid. Add in two more wires and you can put a dash mounted switch to turn it on whenever you feel like it.

If you need a diagram I can draw one up for you.

no no no...

give the thermo switch ground, and then supply the relay with ground.. have constant power at the relay, with switched grounding.. then if you have a short circuit somewhere, the wires have less chance of going up in flames..

[rabbit82]

I would love to have a diagram. Also, which relay do I use?

Still, what could cause the fan to run all the time? What else would have blown the fuse other than a short somewhere? Could the thermo switch be bad and cause that?

[8v-of-fury]

Yes it could be bad, and be stuck in the 'closed' position permanently.

Also Kev, yeah thats a better idea lol. however a short circuit anywhere.. with the 500+ amps wanting to flow through it.. is gonna go up in flames.

Just a standard 4 pin auto relay that is good for more than 20 sustained amps. Assuming you have the stock 250w single speed fan that came in the 82 model year.


excuse the wavy lines, i literally just whipped this up.

[rabbit82]

Thanks, I'll get on this after I get the cv's in. Can't wait to see what is next

[ORCoaster]

A pain in the butt hose break somewhere that will be very hard to find except that you will know it leaks because the fan will once again be on all the time.

[8v-of-fury]

If you've lost enough coolant for that to happen, you'd notice a drop in the reservoir.

[ORCoaster]

Who Checks THAT?

Lately my thermostat has been hanging once the engine cools for the night.  It must have to heat pretty good then pops off send a surge of hot water to the rest of the system.  Or something like that because I will have steam rolling out from under the hood and when I pull over to refill the reservoir it is empty.  I have corrected two bad hoses that were not swapped out prior.  I have a new thermo but not the time to get it in.  I know you can relate to that!

Hope to get the time and weather to do so next weekend.

[R.O.R-2.0]

Yes it could be bad, and be stuck in the 'closed' position permanently.

Also Kev, yeah thats a better idea lol. however a short circuit anywhere.. with the 500+ amps wanting to flow through it.. is gonna go up in flames.

Just a standard 4 pin auto relay that is good for more than 20 sustained amps. Assuming you have the stock 250w single speed fan that came in the 82 model year.


excuse the wavy lines, i literally just whipped this up.

i would make it so that the relay received power from the key.. so it wouldnt have after run.. the only time ive actually seen after run work, is on a black car, on a 100* day..

[8v-of-fury]

Really? Then your auxiliary fan switch was faulty. A properly functioning aux fan switch should kick the fan on when the bottom of the fan reaches a few degrees hotter than the thermostat. And that could very well be after you shut down.

The after-run was put there by Volkswagen, and its a system I feel that shouldn't be removed.

My after-run comes on frequently in the summer, and it doesn't even get that hot here. OP lives in NC, I think he should retain the after-run.

[rabbit82]

OK, this is where I am at on the fuse blowing. I put in a new fuse and used a jumper at the thermo switch and the fan came on and ran correct. The one thing that may be the problem was the PO had cut the two wires at the thermo switch and when reconnecting them just twisted them together and put duct tape on them. I spliced/crimped them back together. Could the weak connection he had not be drawing enough current and over drawing on the other side and just asking to much of the fuse and it blew? The other thing that doesn't make sense with this scenario is that the fan was running all of the time when the engine was running. Could the thermo switch be going bad, maybe bumping around is making it open and close?
From reading above am I understanding the after run correctly, it is only running when the fan motor is hot? Or does it run from the thermo switch only?
Hopefully I will be driving this in a couple of days and I will know for sure how it is working.

[DieselBalz]

i would make it so that the relay received power from the key.. so it wouldnt have after run.. the only time ive actually seen after run work, is on a black car, on a 100* day..

  Thats cause you live near Santa. Come down here to the FLA and you can watch mine run everyday, May through November. Less so during the rest of the months. Especially if I am downtown doin the stoplight hussle on the way to work. Doesnt run long though maybe a minute or two.

[8v-of-fury]

I'm further north then R.O.R and Just yesterday I had my after run come on! And I didnt even drive that far nor hard.. and it was maybe 17c out

[ORCoaster]

Could your high temps and after run have ANYTHING with the way you drive it?  These Portland Peoples knock me out with their stop and go.  I truly believe they have no concept of slow and steady wins the race.