I have the opposite problem. I had the water pump, thermostat, all hoses radiator, radiator cap, thermostat sensor replaced. The car heats up but when i turn on the AC the Temp goes down. I replace it with all OEM parts.
1991 Honda Accord EX

 

Moved to Accord forum.

 

Hi,

I had the same trouble when I first bought my 92 EX, second-handed.

The fan would only come on either when the a/c was on or when I pulled the key from the ignition.

Strange as this symptom sounds like, the whole thing was down to one small and inexpensive part.

If you pull the pannel underneath the steering wheel on the left and close to the bonnet opening lever, you'll find there's a small black box with a PBC inside. That unit's the controller for the car's cooling system. If it's not working properly it can easilly be the source of your problem.

Best of luck.

 

Jump the wires that go to thermo a (on the t-stat) with the key on....do the fans (both) come on?

 

Its your thermostat. I had the same exact problem onmy 94 Honda accord. The thermostat is under you hood. I used a big open end wrench. There's a wire with a plug going to it. Take off the plug, u will see to silver terminal. Bring you cat up to temperature when the needle starts to come up for the fan to come on. I used a metal paper clip and jumped it accorss the two terminals and the fan kicked on. I changed the thermostat, and problem solved