87 4.0 cherokee overheating

replaced thermostat, lower radiator hose, and fan switch (fan runs when bypassed but not when supposed to) There are two relays on drivers side, outer wall- does either one of these control the switch? Or could it be the temp. sensor?, and how do you test it? Haynes manual does not have any info on the relays. Also at what temp should the fan switch open? HELP! I am so confused.

Its a bit of work, and a bit of expence but this will take care of your cooling problems.

http://www.automotiveforums.com/vbulletin/showthread.php?t=206558