E-Fan Timer installed - CEL problems

Hey all...finsihed up the E-fan timer install as documented in this thread http://www.naxja.org/forum/showthread.php?t=1028190 and I've run into a few problems with codes.

The first code is PO1491 - Rad fan control relay curcuit. This seems to turn off when I disconect the timer circuit. I think that a diode installed inline on the timer relay circuit would solve that.

Would this one work? http://www.radioshack.com/product/index.jsp?productId=2062591#tabsetBasic

I'm also throwing sevreal other codes, not to sure if they are interelated but this is my first concern.

Oh - 2000 Cherokee 4.0/AW4/NP231

Well, I got the above refrenced radio shack diode installed. Here's what happened

Initial install first run the PO1491 code disappeared. Also PO136 stoped as well.

Transmission range sensor code still present, as well PO130. New pending code was something to do with the evap system.

Ten minutes of driving and cycle the fan a few times and I have original codes back.



p1491 - Fan relay
PO130 - O2 sensor
PO136 - O2 sensor
PO0705 - Transmission Range Sensor

Also, my A/C is not working and the idle air purge seleniod is not working. I also have no backup lights.

My next step is to eliminate the E-Fan timer circuit, pull the NSS and clean it and then see what happens. I have a spare CPS (Mopar brand) And might install that toi replace the suspect Napa one.

Any thoughts?

NSS sounds unrelated. Yours could just need cleaning like you said.

The other relay related codes worry me, they're definitely related. Did you add the second relay the way that thread specifies or tap into the wiring to drive the factory relay with the timer as well?

Your plan B. Timer, bosh relay, momentary switch.

Power is pulled from the battrey for the relay, and fuse taps for the switch and timer. Everything has cicuit protection in place. I taped the light blue wire to the fan to power it from the extra relay. Soldered it in place.

The fan timer works awesome, but the other codes render it untenable as a permanent solution to the heat soak.