Went to the IH dealer the other day to get crank seal and new ballancer for my tow truck. So I take Mrs FNJs 91 to blow the stink off ( 135 miles all summer!) so I wash the truck dri it off hop in drive to the IH dealer miles away Ilook down on the floor It was wet I thought it was water from my foot so on my way back making lefts an rights I noticed my grey floor mats turning green ! So if anybody has done this any help would be thankful. By the way picking up new cab for my 90 on Tuesday it is a thing of beauty It needs no work at all.

 

i have to say sadly i have had to do this already in my 93--decided that if it happens again i will just bypass it and leave it alone!! so what exactly do you want to know about it?

 

Done a bunch of them.
Remove coolant hoses. Evac Freon, remove insulation pad,blower motor and cover, disconect A/C lines from heater box (and pressure block), remove 6 (+/- 1) nuts that hold the heater box to the fire wall,
Inside truck,
remove glove box door, right kick pannel, heater controll, two screws that hold the air deflector (over the center hump) and deflector, two screws that hold air blend pannel(tucks up under the dash center) and blend pannel, dash brace( near the upper left corner of glove box opening), lower dash attaching bolt (just under the dash, right side kick pannel) ans one attaching screw just above accelorator pedal.
Disconect elec conections from heater box, remove vacume lines & gromet from firewall, disconect blend cable (right side of mount under cable gently press tab in and pull cable straight up) remove heater box attaching bolt(under heater box on kick pannel)
Pull dash twords seat enough to let the lower dash mount catch on the door opening
pull heater box away from firewall. lower from under dash while turning firewall side of box twords floor. should slide out.

10 min easy

Hope this helps

 

Have someone else do it