Topic: Heater blower test

[slk25]

I have a 66 non-ac heater from SJ
I am trying to determine if my 3position switch is bad or the resistor block
The current symptoms are only two of three speeds and the resistor seems to have a short so all the blades seem to show almost no resistance when I put the vom on them
Any clues would be helpful.

[jwc66k]

The dash mounted switch selects the speed from the resistor block by providing a ground. It's been a while, but pull the three pin plug, leave the single pin wire attached, and with the ignition switch to the accessory position, ground each of the three terminals with a jumper wire. If the resistors are OK the fan will operate. Power to the fan comes from the ignition switch, thru a fuse, out to the engine compartment to the fan, the return line is that single wire on the resistor block so don't be concerned with sparks or blowing a fuse.
Jim

[slk25]

Thank you, I will try that

[Brian Conway]

     On the subject of heater the blower switch;  The 65 Owners Manual  pg. 43 states that the switch has three positions HIGH, OFF and LOW in that order left to right.  The switch in my mid May 65, San Jose GT has four positions.  It seems the positions are; OFF, LOW, MEDIUM and HIGH.  I don't have a 66 Owners Manual so would someone care to verify those positions ?  The 66 Shop Manual does not address this.  The Three or Four position dash controls may be relevant to the poster's question ?  Brian

[midlife]

Only the 64.5's and early 65's had two speed heaters.  After the transition to the later style (March???), all heater blower motors were three speeds.

[slk25]

Thank you guys
I did the grounding resistor test and got three speeds from the motor
I replaced the switch and now have good operation without wiggling the switch handle to turn on

[Bob Gaines]

     On the subject of heater the blower switch;  The 65 Owners Manual  pg. 43 states that the switch has three positions HIGH, OFF and LOW in that order left to right.  The switch in my mid May 65, San Jose GT has four positions.  It seems the positions are; OFF, LOW, MEDIUM and HIGH.  I don't have a 66 Owners Manual so would someone care to verify those positions ?  The 66 Shop Manual does not address this.  The Three or Four position dash controls may be relevant to the poster's question ?  Brian

There are several different revised editions of the 65 Mustang owners manuals that no doubt were done to address this and other issues.