Hi, hopefully you can help as no one else can. I have a 1999 PLYMOUTH Grand Voyager, 3.3L. I had to replace my radiator and I had a hose that was bad and my van was overheating when stopping at lights, in traffic etc. Temp would go down while driving. Ok, I replaced the radiator, the temperature sensor, the coolant fan relay which is located under the air filter, I replaced the Thermostat, the speed sensors and the coolant fans were working at first and the van was running great. Now a week later the van is getting hot again and the coolant fans aren't kicking on causing the van to overheat. I checked the 40amp fuse and it's ok. I even turned on the a/c to see if the fans would engage and nothing. The fans are the only thing I haven't replaced. This is really nickel and dining me plus I replaced just about everything. I took it back to the mechanic who did work on my van. He tested the fans and they work, he said he tested the power and ground to the fans and there was power and ground, I don't think he tested the power and ground to the fans when it got hot and when they should kick on but just tested that they worked. He even changed the new coolant fans relay sensor because it was under warranty. The Van still gets hot standing still and the fans won't kick on to cool it off. He said he has no idea why. I don't know why the fans won't kick on when it's sitting and gets hot. Is there wires to check etc. What are your thoughts and what can I do? Thanks🤷🏻♂️
Well either the thermal switch that turns the fan on through the computer isn't working or the wiring from it to the computer back to the relay back to the fans is bad or the computer itself has a bad driver circuit and knowing those products a lot of times it is the computer
Thank you Scotty! 😺
If it's a computer malfunction you can always hotwire the fans to be operated manually from a switch. You'd want to use a relay and fuse the new circuit, of course, but if the computer or wiring harness is bad it'll be the least expensive workaround.
Thanks, its just that i wouldn't even know how to do that and the mechanical ability here in T or C, NM seems to be very limited.
Really it's a simple electrical hookup, not much mechanical ability needed. There are numerous videos on youtube showing how to do it if you search for "manual cooling fan switch". However I'd probably try replacing the temperature sensor that controls the fans and the fan relay first.
The temperature coolant sensor was changed on July 26th the fans started working for a week then started not coming on again, the coolant fan relay sensor was again changed 2 days ago so you're advising to change them again? 🤔 Thanks
Unfortunately these days it's very common for new parts to be bad. Even OEM parts in many cases have been cheapened in design with production moved to China or Mexico. Aftermarket can be even worse. So as much as I dislike the parts cannon approach, if they're inexpensive parts it may be worth doing that before taking the step of rewiring the fans for manual operation. Or those parts can be tested if you can look up the specs for them and rig an appropriate test setup. Unfortunately the only way you can test the computer is with a dealer-level scan tool.
Thank you for all of your advice. 👍
Now i understand why Chuck drives older cars!
Computer this, computer that, Uhhhhhhhhhh check the codes. I dunno, did you check the codes?
Yes, i checked the codes a day after the mechanic changed the coolant fans relay sensor for the second time and no codes came up.