Major Cooling/Fan issues

[4wheelsqueal]

The problems are in 713/1000. First the cooling issue. After starting, the check engine light comes on after 3-5 minutes. Hooked up a Snap-On logger and the coolant temp was reading 252 degree and climbed quickly to 316 degrees which i think is the limit of the coolant temp sensor. got out the infared heat sensor and the block, theromstat housing and the outside temp of the sensor all read about 168 degrees. There is a new ecm sensor and a new coolant temp sensor installed.I did solder on new plugs the ecm, coolant temp and ac fan switch sensor and after this was done, i noticed that the ecm sensor and the coolant temp sensor both have yellow with green strip wires. i did ground the coolant temp wire and it was in normal range and when the wire is unplugged, it reads -85 degrees. Now the fan issue. when i picked up the car, it did not have the passenger side main fan wiring that included the transistor, radiator temp sensor and fan wiring. i used a 1g dsm light plug and copied the wiring location from 555/2000. The fan has power on all the time. No key on, stone cold motor, unplugging radiator sensor, unplugging transistor, doesn;t matter. the only thing that shuts off the fan is pulling the 30 amp fan fuse under the hood. Also the a/c fan turns on after 5 min of starting the car and stays on the whole time. The a/c button in the car doesn;t turn it off or on even after replaceing the a/c button and changing the transistor pack. i have had the ecu gone thru and repaired by steve the ecu guy. Any idea's? have tried searching for these problems on here but haven't found anything on these problems.

 

[524of1000]

I had the same issue. IDK what caused it, and after searching the wires and finding nada, I cut the main power line to the resistor and ran a wire to a switch inside the cabin so I have to turn it off and on myself. Kind of a PITA, but it's whatever. /ubbthreads/images/graemlins/dunno.gif

 

[toybreaker]

I'm a few beers into the night, so I'm not sure I'm reading your post correctly, but it sounds like the ecu temp sender yellow/green wire and the instrument panel temperatute gauge yellow/green wire may be crossed up.

Quote:

i did ground the coolant temp wire and it was in normal range and when the wire is unplugged,



Are you talking about the single pin sender for the gauge?

Grounding the single pin wire should bury the temperature gauge in the instrument panel

Quote:

and when the wire is unplugged, it reads -85 degrees



and the temp as seen by the (two pin) temp sender the ecu "sees" and reports on the scanner should not change at all when the single pin (temperature gauge in the instrument panel) temp sensor is unplugged.

An easy way to check for crossed green/yellow wires at the temp senders is to ohm out the wires.

The yellow/green wire at the two pin connector in the engine compartment runs out to the ecu at terminal #20.

The green with black wire from the two pin connector goes over to the ecu at ecu terminal #24

The other yellow/green wire from the single pin connector only goes to the gauge in the instruement panel.

I only know this because I have crossed them up myself, and the car did some weird-ass sh*t /ubbthreads/images/graemlins/rofl.gif

 

[4wheelsqueal]

When I disconnect the single wire off the coolant temp sensor, the code reader shows the temp drop from 316 to -85 so maybe i do have the two yellow w/green strip wires crossed. anybody have any idea about the fans? have thought about running a siwtch into the car for the amin fan but does anybody have an idea about the a/c fan issue? could the sensor in the back of the thermostat housing be bad? and what is that sensor called? Can;t find it in caps.

 

[doelcow]

Our cars have a high fan and low fan relay. The radiator fan always has a powered lead (even when the car is off) and the ground to the fan is switched via relay. When the thermoswitch in your radiator hasn't tripped yet your a/c can still cut the low relay on (which has a resistor between ground and the fan). I would check both relays and make sure they are functioning correctly and aren't stuck in the on position. My electrical manual is at my shop right now but I'll scan you a diagram tomorrow.

 

[doelcow]

Hope this helps:

 

[4wheelsqueal]

thank you sir! was looking for that!

 

[kaptainballistik]

Ok, the pesky water temp sensor....

You will find that it will go to over 115 degrees when at about 95-97 but will be ok at around 80.... Its coaught a few rallypeople out..