dclong

86 manual controls, AC/Heater blower will not run on High. Low, and medium speeds work fine. I've searched other threads, done some testing, and think maybe the fan motor itself is the problem?

There is voltage at the appropriate pins on the Relay at each fan switch setting. With the Relay removed, I can run a jumper from the 12v Red wire to the Red/black wire and the fan runs on high, so I thought it must be a bad Relay. $7.99 for a new one, so not much harm in trying.

Put in a new Relay, switched to high fan setting, and it blew the 25amp fuse on the main fuse panel, and the new relay was so hot I could barely touch it.

I replaced the 25amp fuse, put in the old relay, and back to having all speeds except high.

So is the Fan motor drawing too much current when trying to run on HIGH? How do I test the fan motor to see if it is bad?

I can do about anything mechanical. Electrical - not so much. I can use a basic volt meter, but my that's about it.

LD85

Exact same problem, did you figure it out?

oldalaskaman

how bout the resister?

LD85

It's intact, not broken, I'll get a new one just because its old ($18) and this weekend I'll pull the blower motor and check the voltages per the manual, a motor is only $20 so I'll probably replace it too.

I do PM/replace old parts that are still stock i.e 1985 original whenever I take the old stuff out if it is $25 or less kind of cost, with my luck it always does after I put the old stuff back in so I figure its better to just replace it

oldalaskaman

mines the opposite, only runs on high, probably fix it .....sometime around summer

dsandmire

Ditto--the fan on my 87 only runs on high--be curious to hear if you find the cause, switch, relay, motor, etc....PS== were is the fan relay located?????

LD85

The schematic looks pretty basic, I'll know more next Saturday, have to take he pass side wheel well out

oldalaskaman

http://www.justanswer.com/uploads/su...0157_relay.gif
this should work, the relay is usually the one with the stainless cover

vetteoz

Check for power in / out of resistor when on Lo / Med settings
If you have power in ; then switch is OK
If you have power out then resistors are OK