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Hello. I am sorry to see nobody has answered your question for so long. I just logged on and noticed your question and thought I would reply since earlier this year we had the same exact issue on a 98 VW new beetle and the problem was the cooling fan control module. It is not an uncommon part to fail on these cars. It is however important to replace it with an original VW part. There are aftermarket modules but when we had this issue we used an aftermarket and it lasted only a couple weeks and came back with the fans now refusing to turn off and killing the battery. We replaced that one with an original VW module and it is still working great. I have attached a picture of the module that I am referring to. Is this the part that you have replaced?
I don't think the problem is the water pump either. Do you have a diesel or gas engine? I apologize if you provided that information earlier, but it's not showing up for me.
Ok. It only matters for checking TSBs. You have replaced the thermo switch and the module that I have pictured? What exactly have you replaced? I just want to make sure I know all the details. If you have not replaced the thermo switch then I would like to walk you through testing it to see if it's bad or not. If you have replaced it, then I wont put you through that. Although I suspect the fan control module is at fault, it could be the thermo switch and unfortunately the fan control module has no direct testing, so we need to rule out other possibilities to be sure it's the fan control module.
I understand.. We will do what we can to get the little bug back in order.
Alright, so you have verified that the cooling fans are in fact functional by directly applying power to the fans and saw them run..
You have replaced the thermo switch located in the bottom left of the radiator, so we can rule out a bad thermo switch, so testing it at this point really isn't indicated.
There should be a red wire at the thermo switch, check to see if that has power. It should.
If it does have power then I am going to put my bets on the fan control module, but just to be sure, when you say you replaced teh fan temp module, are you talking about the module that I sent you in that picture?
When ever you get back to me is perfectly fine.. no rush.
I think the issue with aftermarket is more of a quality issue. I have installed the aftermarket module only to have it go bad after a short time. I would think if you installed an aftermarket part, it probably would have worked at least for a little bit. If the behavior of the fans is exactly the same with the new module as it was with the old module, then it looks like the module is not the problem. I am going to opt out. hopefully one of the other techs knows what is going on and can get your fans working again. With everything you have tried, I am at a loss at the moment.
Have you actually tested the water pump to make sure you have flow? Just disconnect the small line at the coolant overflow reservoir, point it into the top of the reservoir, and have someone rev the engine to about 2000rpm. You should have steady flow with no excessive ai or spitting, and it should increase with rpm. The water pump on these is notoriously bad, it will break into pieces, or it will simply crack and may flow a little but will mostly spin on the shaft. You could have hot hoses just because the engine is getting overheated.
Also, the strip fuse block on the battery- did you pull out and check all the green 30 fuses there? They will often melt down without blowing. Check the thick wire from the positive terminal to this fuse block to see if it is discolored due to heat.
OK- if you can turn on the A/C switch and the fans will still not come on, then you have an issue for just the fans. And you said jumping the temp switch at the radiator you were able to get the fans to kick on. I would suspect the fan control module under the frame rail then. Check for battery positive on the red power wires, check and clean up your grounds since you are under the battery area.
Ok, no hurry
I would make sure to check the coolant flow, just to make sure it is OK. But it sounds like your issue is with the fan control module under the frame rail (under the battery area)
Yes- so if the pump is not circulating coolant, those hoses will get hot just because the whole system is getting hot. But the thermostat will not open, and the fans will not kick on.
OK- the pump is driven by the timing belt, but I have been able to replace it without having to completely remove the timing belt (though it is tricky. So I would make sure to set the engine up at Top Dead Center in case you lose your timing references with regards ***** ***** belt.