Ok so i was sitting in the parking lot the other night letting my car idle because my friends wanted to hear it with the cam and what not. Earlier that night my SES came on and then when I got back in the car it was still on but i just figured it was a fluke. So anyways I start smelling coolant and so i decide to go check the tempature and sure enough it's getting close to the red. I just had my whole engine rebuilt and i dont want another blown headgasket. So i found out that my fans aren't turning on. I've read that if the SES light is on the the fans are supposed to turn on because it's kind of a protection mode or something but mine don't. I then found the 10 amp fuse that says Fan ACC or something blown so i replaced that and now i don't get a SES light. I also took all the fan relay's and put them in the fog light place and they all worked for the fog lights so those aren't bad either. I tried unplugging my battery to reset everything and also checked the connection on the fans. Also if i turn my AC on the fans still won't come on. So for some reason i blew that fuse and now my fans arent working. What else could it be/ can i check?

 

Update I just jumped pins 5 and 6 on the ob2 connector piece (dlc) and the fans work when i do that. So what does this mean?

 

You are putting the PCM into field service mode. Not sure exactly what happens when it does though. Can't find a description of it's actions in the shop manual.

You got to scan it for codes. Remember it's the OBDII connector but the system is OBDI, so places like AZ can't scan it.

Because you are getting output from the PCM to turn on the fans, it would appear that an input to the PCM is corrupt. BUT, you tried different (unrelated) inputs to cause an output. ???????? Even the grounds for the signals are not common. Unless I missed something???

 

On the bottom of the waterpump is a sensor which is your ECT(engine coolant temp sensor). If this goes out, your fans will no longer come on. They are a few bucks up at your local parts store. But when replacing it, be careful not to get to much coolant on the opti.

 

OK i'm going to go get a ECT and see if that fixes my problem. I think it might but the only thing i don't understand is why the fans don't come on when i turn on my A/C.

 

the egr solenoid will cause the fans fuse to blow. if you ireach back on the drivers side of the intake you'll find the solenoid there unplug the conector and then put in a new fuse. start the car and turn the a/c on and see if the fans run. i had the same problem in my car once and i couldn't belive and power for that runs the fans and the egr solenoid. the ses light will be on till you get a new solenoid but at least the fans run.

 

Is your A/C working? I think I heard that the fans will turn on when the A/C system's pressure reaches a certain point... if you're low on R-134a, the system might not reach the required pressure to turn the fans on.

 

Yea my A/C and heat works fine. Just i heard with the ac turned on the fans should eventaully turn on also?

 

Regardless of the condition of the ECT signal, the fan should come on with an A/C request. I saw no DTC that would disable the fan during normal operation. Remember the PCM (according to blaze) will turn on the fans when he puts it into field service mode. I did find that when the PCM is put into field service mode, the fans are supposed to come on. Given the fact that the A/C comes on like it is supposed to, you know the PCM is seeing the A/C request.

You also know that the PCM will turn on the fans when put into field service mode. (this is critical so you better double check again). This proves the fuse, relays, fans and wiring are good as well as the PCM output.

That only leaves one possibility. PCM failure.

Scan it and don't throw money at the problem.

 

trust me unplug the egr soleniod then put in a new fuse

 

Well you were right. I went out and unplugged it and started my car up. The fans were on low for a second and then they kicked on high. So atleast they work now.

Thanks

 

who's the man