97 Taurus overheating

Please help!!!! The car was basically given to me, and the previous owner had replaced the water pump, thermostat, and radiator. It will occasionally overheat when stopped for a light, and come out of the overflow. I put a new tank and cap on, in case the cap was worn. But, I noticed the fans don't kick on. How do I tell if it is a relay, or coolant switch, or whatever? I turned the air on also, and the fans didn't kick on with the a/c on.
Any and all help is appreciated.
Paul

The water pump impellers might be worn off.

http://www.automotiveforums.com/vbulletin/showthread.php?t=605107&highlight=fans+dont+come+on

http://www.automotiveforums.com/vbulletin/search.php?searchid=1992959

Your same problem has been hashed out many times so read through the threads. We have a great search engine, look upper right and use "Search This Forum." Using just "search" searches all the forums. One of our electrical experts will be along to help you so research the threads first.

how long ago was the water pump replaced? Does your heat work?

"It will occasionally overheat when stopped for a light, and come out of the overflow. . . . . But, I noticed the fans don't kick on. How do I tell if it is a relay, or coolant switch, or whatever? I turned the air on also, and the fans didn't kick on with the a/c on."

"how long ago was the water pump replaced? Does your heat work?"
From what I read, the fans aren't working and it doesn't matter if the pump is brand new, if the fans don't work and provide enough air flow through the radiator to cool the coolant it will run hot when the vehicle is not in forward motion. Hence we read this: "It will occasionally overheat when stopped for a light and come out of the overflow." Badda-bing! Red Flag - Fans don't work - vehicle standing still overheats? :slap: How about if you let the gauge climb a little then take off down the road. Does it cool off then?

I grant you, there's a slim possibility it is the water pump, but I'd look to the most obvious problem and first order of business would be get the fans working properly and go from there. Sounds like the former owner did all the right things properly maintaining the cooling system and components. Again, IMO it's an electrical component or sensor not doing it's job telling the fans when they should come on.

"How do I tell if it is a relay, or coolant switch, or whatever?" Electronics not my forte but we do have some very fine electrical technicians who will gladly point you in the right direction. Meantime, you might want to find an auto patrts store that pulls codes for free and see if you have codes stored. What year and engine and how many miles on it?

...But, I noticed the fans don't kick on. How do I tell if it is a relay, or coolant switch, or whatever? I turned the air on also, and the fans didn't kick on with the a/c on.
Any and all help is appreciated.
Paul

I'm going to assume you have either a test light or a multimeter to aid you in troubleshooting the electrical portion of the cooling fan dilema.

Check the 40 amp fuse for the cooling fans in the engine compartment fuse/relay box. It should have battery voltage at all times.

If the fuse is good, I'd suggest unplugging the electric cooling fans at the fans and connect a test light (or meter) to the connector for the fans. Both fans are wired in parallel, so you should only need to connect to one of the fan connectors. Start the engine and turn the A/C on. See if you have voltage to the fans. If not, then I'd suggest leaving the light (meter) connected to the Gray/Red wire and connect the other lead to a known good ground. If you now register battery voltage to the fans, then you have a ground issue in the circuit.

If you don't have power to the fan motors, you need to check the Constant Control Relay Module (CCRM) to see if it is getting a fan request signal from the Powertrain Control Module. Plug the fan motors back in. The CCRM is located to the left side of the battery (between the fender and the battery). Check pin 17 of the CCRM (a light green/pink wire). This wire should be at ground potential when the PCM is requesting fan operation.

If pin 17 of the CCRM is at ground potential with the A/C turned on and the compressor clutch engaged, then check for power at pins 6 and 7 (both gray/red wires) of the CCRM for battery voltage.

If you have battery voltage at pins 6 and 7, but not at the motors, you have a problem with the wiring between these points. If you don't have ground potential at pin 17, then you either have a problem with the wiring between the CCRM and the PCM, or the PCM for some reason is not requesting the fans to run. In this case, for sanity, you may want to temporarily ground pin 17 by backprobing the connector and verify the fans work. If so, you may want to find a high end scan tool and check the datastream for the "Fan Request" parameter to see if the PCM thinks it's making the request of the CCRM.

-Rod