Blower won't stop....sometimes Old fedders updarft

[chiknstik]

Ok Icehouse, JW, and Repair-man, here's one fer ya:
I have a 70's era Fedders updraft gas furnace with split AC coil on top (Its in a rental, and I didn't get the number off it this afternoon, sorrry).  In Arkansas.  (temperate weather) Last winter had an issue with blower re-start after furnace shut down.  Adjusted the fan/limit blower off temp down from 100 to 90 degrees.  Problem solved, for then.
Summer problem-sometimes the blower won't stop.  My tenant works odd hours, and every other day is gone for 12-16 hours, so he sets the thermostat up to 82 degrees.  Then, when he comes in (around 2AM) he sets the temp down to 76.  When he does this, about every other time, the system will cool down to set temp, shut off outside condenser unit, but keep blower running.  Cyclying the fan auto/run switch does nothing.  Turn the Cool/off/heat swith to off will not stop blower.
Blower will eventually stop, then system cycles normally, until he's gone for extended period. Then, it may do it again.  Sometimes it doesn't.  Have changed the thermostat, checked for control voltage outside at contactor (26v), checked all wire connections at furnace, tight and clean.  No electronic boards. Fan/limit control is clean and all connections tight.  I can't find a relay for the blower.  Does anybody know if there is one?  Where?  Anybody have a wiring diagram?  If there was one, its apparently long gone.
I'm not a pro, just been at this rental gig a long time. (Do have EPA card for refrigerants.)
Thanks for any ideas.

[JWWebster]

Maybe a bad wall thermistat or a RELAY PROBLEM

[chiknstik]

Like I said, have replaced the thermostat with new digital one.  Can't find a blower relay, but I did read your reply to the guy whose blower won't run, and will look again, after seeing your pics.

[chiknstik]

Weeeell...no other iddeas?  No problem, I figured it out.  Good old Fedders hid the blower relay in the blower compartment, on the underside of the the top panel.  Had to get down on my belly and shine a flashlight up following the motor wires to see it.  Don't ask about getting it out and replaced, but I did last Friday.  So far, no more blower run-on.  Looks like that was it.

[AJ]

Glad to hear you got it repaired. 

Thanks for the update.

[JWWebster]

All you had to do was take 2 bolts loose and slide the blower out. Glad ye got er dun!!! LOL