Lonnie:
I have a 54 3100...same heater as yours...I'm on vacation at the moment..so my info is memory based ( Scary ). I just bought the truck 3 weeks ago and haven't had the chance to really get into her..but the heater I have has the same switch you have. The previous owner attached it to the dash on the left side of the steering wheel. ( white knob.. possibly painted)
Now the cable that operates the little trap door next to the side wall...that cable went under the dash along the firewall to the left side of the dash,next to the switch. it went thru dash with a black knob with " T " on it...I've always thought that was for throttle...so you could set the pace and work in the fields.. But now it stands for Temp...I guess.
I need to get a new cable due to mine being stuck/non moving. I sliced my finger real good trying to get that trap door open...Nothing like spilling blood while working on your truck...Part of the process.
Classic chevy parts sells the switch #68-312 for 12 volt, and I found a Throttle cable with knob # 29-357.
Haven't measured the cable thats on mine yet...Don't know what they used if not the one they are selling.
Also, where are the air/slots on your dash located...I need to get hoses and vent outlets..just don't know where to place them since i can't see any slots from on top side of dash.
If I remember correctly I have a pic on my site of the dash and the heater & T pull knob.
Thanks
Jimmi V.
54 3100
www.photobucket.com/snipe
