Posted: 8/30/2016 1:53:22 AM EDT
| I had my blower motor 3 position switch stop working. This happens last year. From memory the old switch had burned one side up. This is a classic truck that doesn't get driven much when cold so I had put off repair until now. I wired in a new switch, then tested amp draw to see if motor was drawing to many amps. What I found was the power leg was about 4.5 on high and the ground was around 2.6. I am a layman on electrics, my question is should the ground match the amp draw of the positive and if so would that indicate a bad ground ? Thanks |
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No
Not understanding the original problems. Google the make model year and get a schematic look for a series resistor in the schematics. This controls the blower speed on most older trucks. It works by lowering the voltage to the blower motor for slower speeds then it is bypassed for full speed . See if it corresponds to the missing blower speeds |
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Leg? Cars use DC. The switch has an off posiition, a dictecly connected position (high), and a few that connect the load through resistors of decreasing values for low, medium, etc.
If the blower motor resistor pack has blown it's thermal fuse, high speed still works, others won't. This could be a symptom of blocked air flow, or blower motor going bad. |
