So... my 89 XJ has been getting horrible gas mileage and I figured out that the heater wire to the O2 has not been getting power. I traced it back to the starter relay. When I turn the key to "run" this wire on the starter relay should be hot(12v) correct ? I was trying to figure out which wire is going to the starter relay to "turn it on - the O2 heater wire" and put in my own universal relay as I have a few sitting around. Other option is to buy one for about 40 bucks. No time to go junkyarding either. On the starter relay theres 2 green wires - one goes to the starter solidnoid, the other green goes though a plug and then joins the first green wire. Theres one thin black/white wire which I think activates the starter solidnoid wire to start the rig.. which must be momentary only. Other than that.. just the cluster of hot "on" wires.