how can you tell if the Prom chip is Custom/Aftermarket or stock? are they different colors or such?

 

Aftermaret such as JET will have their sticker on it, but if it's a true custom burned PROM I don't think there's a way to tell from looking at it.

 

well i am wondering cause 1. my fan will not turn on with temp but it will for the failsafe and 2. the 2 previous ECUs i had had black carriers and black chips in them, This one i have currently is Brown with a light brown chip. it does say delco on it.

 

If it says delco, then it's factory.

 

Check the F/P - FAN - C/H Fuse under the dash. It's supposed to be a 20 amp fuse and that feeds power to teh relay, then onto the ECM where the ECM grounds the circuit to energize the relay. I think the A/C circuit for the fan is seperate and doesn't use the relay, but I'll find out for you for sure.

 

Ok, the A/C does use the relay to activate the fan, just like the ECM does, so...

What I would suggest is that you check for continuity on the GRN/WHT wire that goes from teh ECM at C1 to the fan relay and make sure that you have a good electrical path there.

If that doesn't work, then you will have to find the Single GRN wire sensor that is supposed to be n the back of the Passenger side head and chcek out that sensor.

Good Luck.

Jeff

 

see thats just it i dont have a sensor back ther only a plug. and i cant even find a wire thats unpluged there.

 

That's where the problem is then. Is the sensor for the light that you have a single wire or a 2 wire? i'm not talking about the CTS.

 

its a single green wire. the fan has always run nonstop the first two ECUs fryed the fan chip so it would come on the second you turned on the ignition now it dont come on till you start the engine. Can you take a Pic of your sensor in the rear pass side head so i know if im looking at the right thing?

 

I'll see what I can come up with for you tonight when I get home

 

Yes, the stock memcals usually have a silver sticker over the "Window" over the eprom that says "Delco" on the top, then 3 or 4 character Alpha code below that, and a 3 or 4 number sequence below that.

But, even this is still not definitively a stock memcal. It possible to remove the silver sticker, erase & reprogram the chip and then place the silver sticker again without anyone (especially smog *****) being the wiser. I've done it a number of times.

 

well till i get this figured out i just went ahead and installed a switch. I had intended to install a switch any way.