Cooling fan not working and no HOT ENG light

[darkred87T]

I had my car out the other night and after it warmed up I noticed it wouldn't respond to throttle past a certain point. I drove home, pulled into the driveway and noticed it was overheating and spewing antifreeze all over the driveway from the overflowing overflow tank. (Why didn't I get a hot light?) I immediatley shut it off and plugged in the Direct scan. I started it up again and saw the temperature was over 230 degrees and the fan wasn't running.
Anyhow, I took it for another ride tonight and watched the tepmerature on the DS. I pulled back into the driveway and let it idle. As the temperature rose above 175, the "FAN" block lights up on the Direct Scan telling me it's calling for the cooling fan to run. I look under the hood and no fan. Temperature reached over 220 very quickly so I shut it off.

To sum it up, my cooling fan does not come on when called for and I get no HOT ENG light.

Here is what I did:
I checked the fan itself by running leads right to the battery from the fan and it works. Then, I checked the plug from the harness to the relay on the fan itself and got voltage on the middle lead. I can also jump the fan through the relay and that works. I also checked the bulb for the HOT ENG light and it works.

Does anyone know where I should start to diagnose the problem? I printed out a wiring diagram from www.gntype.org so that might help. How can I check to see if it's working O.K. up to the realy on the fan?
Sorry about the length, any help would be appreciated.
Mike

 

[Ormand]

The ECM should trigger the fan to start on low speed, somewhere around 200 degrees, maybe less, depending on the chip you have. It grounds one of the terminals on the low speed relay, on the fender on the driver's side. (it will also tell Direct Scan that it has turned on the FAN) The A/C will also trigger that relay. Does the fan come on when you turn on the A/C?
When the engine gets really hot, the "coolant temp overide switch" will ground a terminal on the high speed relay, which is the other small relay on the driver's side fender.
The two relays are powered from the 20a fuse labeled "Gauges", so if that fuse is bad, or there is a bad connection somewhere in the circuit, neither relay would work.
The temp switch for the idiot light may not work when there is not enough coolant in the engine- I've had that problem on a couple of cars. I guess it gets a steam bubble or something, that fools it into the engine is not really hot. That may be true of the "overide switch" too, don't know about that one.
The thing on the fans is a resistor, not a relay.
I would start by checking at the relays on the fender- they are often a problem.

 

[darkred87T]

Thanks, I figured out that I didn't have all the grounds terminated AND I somehow I pulled the connecters right out of the plug on the Fan Delay Relay. It proabaly happened when I was installing my line lock because it was in the same area. Anyhow, in an attempt to put the connectors back in the right order in the plug, I got them reversed.

Now I have everything hooked back up right again and the fan cycles on and off fine with the car running but as soon as I shut the car off, the fan won't stop running. It only stops when I turn the key to the On position, (the oppostie of what it's supposed to do). I guess the Delay Relay is not resetting? Maybe I screwed it up when I crossed the connections. Do I need a new relay or do I still have a bad ground somewhere?

I checked the Auto Parts store and they want $65 dollars for a new Delay Relay.

 

[darkred87T]

Well, I figured it out and all I had to do was unplug the Fan Delay Relay. Duh! I thought the fan would'nt work with out it but it apparently it gets it's juice from an ignition lead while the car is running.

Oh well, alot of time and frustration spent for nothing but a good lesson on how that stuff works.