I got woken up from my Sunday snooze by my neighbor because when she refills the coolant reservoir the water runs out immediately from the radiator to the ground from the radiator of her 1999 Opel Corsa Sedan. I had a look, and told her she would need a new radiator. On Monday she gave me the money I went to buy the radiator. In the process of replacing it, as it's so often the case in DIY there was a problem. The fan was loose from it's housing and as it turns out this was the reason for the hole in the radiator.
It seems someone had done this work before. I assume there was something wrong with OEM fan and this person thought to save money, they would not replace it with an OEM version. They bought a very cheap generic fan and attached it to the OEM housing with cable ties. This was a bad idea because cable ties aren't great at holding things that move. The fan had clearly broken off it's cable tie restraints and smashed into the radiator and a big bolt in front of the fan started grinding against the radiator fins and pipes till it punctured it.
So I told her we need a new fan assembly. She agreed, I went and bought a new fan assembly, basically a fan and it's housing attached together the way Opel intended. When I attached the fan I rand into a problem. The old fan had male connector, which connected to a female one on the fan harness. Not only that, the new fan's connector was female and was much larger than the one on the car. I went looking for a big male connector, but no one sold it.
I decided I was gonna make something. I cut off the cable from the old fan with its connector. On the cut side, I stripped the wires and crimped a couple of electrical connectors. so instead of worrying about the big male connector I don't have and can't find, I used the electrical connectors and the other end that has a male connector, I connected to the harness as it used to be. I thought great, job well done. Yes you guessed it, not even close.
I took the car out for a test drive, the car was just getting hot and the fan was not coming on. It was now dark, I had my tester out, no power was coming to the fan. No fuse was blown, Continuity was there on the wires, on the connectors and on the fuses. As per usual, I was now frustrated. Unfortunately though once someone has given you money you have to give them back something that works. I called it a night.
The following day I must have taken the fan assembly out and put it back in 3 or 4 times with no luck. I ran the car, again the car overheated and burst a plastic pipe that connects the reservoir to the water pump, radiator and the climate system inside the car. A small, about 2cm crack appeared and steam came out. I let the car cool down and decided i wouldn't worry about it for now. I was going to prioritize the fan.
I was really not looking forward to returning this fan. Not only because it would be inconvenient but also because the uncomfortable nature of a return. So before I put myself through that I thought I should make sure the fan doesn't work. I, for what felt like the millionth time, took the fan assembly out, I got my jumper cables and connected the fan directly to the battery. The sweet relief of a working fan came about. So the fan works great but the problem still persists, when it's connected to its wires it doesn't.
I followed the fan harness all the way into the car through the firewall. I thought it was wired that it seems to be independent. I looked at the fuse box again in the light of day and something jumped out at me. There was 2 wires, one earthed on the metal casing of the fuse box and the other squeezed into the prong of the big fan fuse. This means that the guy who put in the cheap fan, by passed the regular harness, which means the thermostat which at this stage I thought might be the problem, has nothing to do with the fan anymore. The fan has been wired directly into the fuse. So what switches the fan on? Surprise surprise, there is an unlabelled toggle switch on the dashboard that the owner neglected to tell me about. I flicked the switch and the fan came on. Knowing about this switch would have saved me a day.
I went looking for the plastic pipe, couldn't find and got to the last store just after it closed. That meant another day of this seemingly simple problem not solved. The following day I got the pipe and put it in and the war was won.