P1491 AFTER fan switch bypass added?

AH!

I got it working. I installed the second relay and I can activate it.

When I flipped on the A/C, the E-Fan came on like it should have, the A/C started working and also the check engine light came on.

I'm not sure what I should look into next? I tried jiggling the wires and the relay with it running and the fan kept running. Doesn't look to be a loose wire in that case.

Any suggestions?

P1491 Radiator Fan Control Relay Circuit

How did you accomplish the bypass?
If you grounded out the wire going from the PCM to the fan relay; that is your problem.

There has been countless discussions on the way different owners have accomplished this...., but for me cutting one wire at the harness connector for the auxiliary fan then connect it to a 87/87a relay. Manually switch the ground leg to engage the magnetic coil on the new relay is what I did 10 years ago without any codes or problems.....

I lived with the 1491 for two years until last week when I finally added a relay which shields the pcm from your switch. I am finally CEL free(maybe I should give it a couple more days). Here is what FyrFytr came up with: http://www.naxja.org/forum/showthread.php?t=1025399&highlight=fan+ride+switch

I read Charles' post in another thread, and (after fighting relay control circuit codes while fooling with an override setup) just put the relay on the fan pigtail, and it's been fine.

Crude schematic


Override switch off, it works normally. Switch on, fan runs whenever the key is on.

I followed this

http://www.naxja.org/forum/showthread.php?t=1025399&highlight=fan+ride+switch

Would it be possible I put the wires going to the PDC and PCM bakcwards? Whuld this cause a problem?


I tapped into the DBPK wire by the air filter.

Where is the power distribution center and the powertrane control module?

The PCM is next to the airbox- the aluminum module with the three large electrical connectors. The PDC is the fuse/relay block on the passenger side.

Did you tap into the blue/pink wire, or did you cut it?

Innnnnteresting. The Dark Blue / White wire isn't always providing power. That explains why sometimes the engine computer could turn on the fan in this configuration and sometimes it couldn't.

Brought it to a friend of mine who is much much much much much better with wiring. He was able to figure this out.

So right now I have it wired up, but the relay is always hot because its wired to the battery. (I just pull the wire off of the terminal when I shut the jeep off).

Anyway, I'm able to operate the fan by switch with no check engine light and when I flip on the AC the computer is able to operate the fan with no check engine light.