I have a 1997ish intertherm A/C unit, when the Air is on the blower works fine, but when I switch to heat or fan only the blower will not work? I have bought a new blower relay & capacitors. I tested the sequencers for 240 & 24 volt, everything is reading good. I am at a loss, does anyone have any ideas? Thanks in advance.

When you call for heat or just fan from the t-stat the blower will run on low speed. Make sure the low blower speed is hooked up.