If the fan is constantly running, I wonder if other things on the power train relay circuit are hot too.
Powertrain Relay Diagnosis
Powertrain Relay Diagnosis
Circuit Description
The
powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The powertrain control module (PCM) supplies the ground path to the relay coil control circuit, via an internal integrated circuit called an output driver module (ODM). When the PCM commands the relay ON, the relay coil creates an electromagnetic field. This electromagnetic field overcomes the spring tension and pulls the armature contact into the stationary contact of the relay load circuit. The closing of the relay contacts allows current to flow from the battery to the following fuses and relay:
- PCM fuse
- ECM fuse
- INJECTORS IGN MOD fuse
- EMISSION fuse
- AFTR relay
- AIR PUMP relay
- AIR SOLENOID relay
- A/C CLUTCH relay
When the ignition switch is turned to the OFF position, power is interrupted to the ODM in the PCM, and the relay electromagnetic field collapses. This allows the spring tension to separate the relay armature contact from the relay load circuit contact, which interrupts current flow to the fuses.
So this problem has resurfaced and I'm looking for some help.
Here is an updated schematic on what I have done:
With the key off - the coolant pump is running - HE Fan is NOT running. Here is some additional information and things I have checked:
1. AFTR COOL Relay has been verified OK with multimeter - I've even tried other relays in its spot with same results.
2. Powertrain Relay has been verified OK with mulitmeter - I've even tried other relays in its spot with same results.
3. All grounds on car have all been verified. Coolant pump is grounded to engine block.
4. Coolant pump wiring from factory has been verified to be correct (some reports of the +/- being reversed from factory).
5. If pull the AFTR COOL relay and jump terminals 85 and 86 on the AFTR COOL relay slot on the fuse box, the HE FAN will come on.
6. If pull the AFTR COOL relay and jump terminals 30 and 87 on the AFTR COOL relay slot on the fuse box, the coolant pump will come on.
7. If I remove the jumper wire I installed to trigger the HE fan, the coolant pump will not run with key off.
8. If I remove the COOL FAN 2 relay, while the AFTR COOL relay is installed, the pump will quit running with key off. This is the one I'm having a hard time understanding.
9. I have verified that the circuits behind the POWERTRAIN relay are not hot with key off. I did this by pulling the fuses and checking current across them with a multimeter.
What am I missing? I'm about ready to dump this idea and just add a seperate relay for the HE Fan that is triggered by RUN.