kingo2014

86 with manual controls--blower works on high only

I've replaced the resistor and the switch. can the blower motor itself only work on high? someone said "possibly a short or loose wire" thought I'd try the easier things first. I have NOT changed blower motor.
any ideas? thanks,

Hooked on Vettes

Unplug the Blower Motor Relay from the socket and verify the wiring and socket contacts are good. The Dark Blue wire at the relay socket should have a different voltage on it at different
fan speed settings. In Hi speed there will be zero volts on the Dark Blue wire.

If the Dark Blue wire has voltage the blower should run. If it doesn't the normally closed contacts in the relay are bad. You can pry the cover off of the relay and file the contacts or buy a new relay.

excellencee

My '86 did the same thing. I verified the voltages with the FSM and they were all good. $10.95 for a relay and everything is good now.