97 Toyota Camry

I doubt that the Trailer wiring has anything to do with the cooling fans not working. Try this.....with the engine running....turn on the AC to Max....high blower speed. Do the cooling fans now work?

Yes, the fans are cutting on when the AC is on. I've replaced every sensor from the coolant sender, coolant sensors, and low pressure AC sensor, and now the fans don't want to cut off. It started when I replaced the low pressure sensor.

What about the 2 wire sensor in the radiator. I think it's on the right side...passenger side of the radiator? Was that sensor replaced?

Are you talking about the one at the bottom of the radiator on the passenger side?

Yes....has that one been changed with a new part?

Yes, that one has been changed as well. Even the low-pressure sensor on the other side of the radiator behind the grill.

The fans would only cut on when the AC was running with the old low-pressure switch, but since I've changed to the new one, the fans run nonstop.

Hmmmm... ok...as I recall there are 3 Relays which control the Fans. One of them may be causing the issue....but,,,which one? Sooo...lets make sure I understand the revised issue. The fans run allllll the time..... even as soon as you turn the key on engine off and Heat and AC OFF?

AND....with the engine running COLD...the fans continue to run until you shut the engine OFF. Fans turn off when Ign. key is off. Correct?

Another thought. Concerning that AC Pressure Switch. When you replaced it.....did you loose any Freon?

Yes, the fans are running as soon as you turn the ignition on period now, even without cranking the engine. Then they run until you turn the ignition off. Before we replaced the low-pressure switch, they would only cut on if you unplugged the fans or turn the AC on. We refilled the AC system after replacing the low-pressure switch.

OK....I seem to recall there are 3 relays which control when those cooling fans will run and how fast they will run. Look for RELAY #!.......RELAY #2....and RELAY #3. I think they are all located under hood. Removing the cover on these relay/fuse boxes and looking at the UNDERSIDE of each cover. there should be a legend ...ID...of said Relays. With the Engine COLD turn the key to the ON position. Seems to me...there is no reason for the Cooling fans to be running. Do not start the engine and pull/remove relay # 1.......what happens?

What happened? If the fans turned OFF with relay #1 removed.....buy a new relay. make sure it matches up with the old relay........and plug it in. Get back with results.

Don....give us the good news first!