My ignition was turned off with the key still in it when I hooked up the negative battery connection, I heard a loud POP. Now my Air Pump, AC and Cooling fans do not operate. However, bypassing the computer, I can get them all to work by applying direct power to the relay for each item.

Is it possible that by not removing my key from the ignition altogether that it damaged the computer for these functions? The fusible link and the relay for each these functions appear to be fine.

Any suggestions at this point would be greatly appreciated. Thanks in advance!

Bob

 

I know this may seem like a really simple answer, but have you checked all of the fuses in the fuse box? The ones next to the driver's door? See if all of those are still intact, then let us know what happens.

Good luck and kill Rustanks!!


x01660

 

Also recheck the fusible links, they melt under the insulation and look good even though they are bad. All 3 circuits you mentioned get power directly through fusible links ( no power fuses for these circuits). The PCM only controls the relay coils by applying ground. Also check fuse #6 (FANS/ACTR), and fuse #7 (AIR PUMP), both in under hood fuse box. These fuses provide power to the relay coils.

 

Thanks!

 

The loud pop was a power surge at the battery connection, an arc that caused the air to ionize and make a noise. For some reason your car was drawing a lot of power. I imagine the switch was turned on and the accessories were drawing alot of power . That alone wouldn't cause all the fuses to blow though.

 

Z28Pete, thanks for the response. I have checked what I believe to be all the fusible links coming directly from the battery--the only ones I could find anywhere. All the links have power on both ends. Checking the underhood fuses and relays, I find that I can trip the fans bypassing the relay trip. Now, what I think is happening is that the relay is not getting the signal to cause it to engage the hot side to the fan and A/C power. The manual schematics show the trip circuit going to the computer and back to the fans and A/C compressor. The sensor and the air pump have been replaced with new. I am at a loss.

Are there other fusible links hidden somewhere? Any clues would be appreciated. Thanks guys!

 

Thanks Psycho. I'm stumped on this car!

 

pull the under hood fuse box and see if theres any damage on the underside. pull the wires off the power junction box(red plastic box on the passenger side fenderwell) clean and check for damage. pull the ground wires off the ground junction next to the power junction. check and clean them as well. it may be worth checking the ground wires on the front of the block on the diver side as well.

 

I believe the sensor on the water pump has to call for the fans at a preprogrammed temp (160-180) before the relay comes on.
I don't know if there is a way to fool the computer into thinking that the temp is high enough for the relay to come on.

 

Unplug the connector at the ECT sensor and short the two wires going back to the PCM to each other. This will make the PCM think that the engine is running red hot, and the PCM will signal the fan relays to turn on the fans.