revisit blower motor

[andy blackmon]

After replacing the blower switch, the resistor, the relay, the blower motor, and checking the #10 fuse, made sure that i had the 30 amp breaker -----4th speed on my blower fan still does not work. While i can live without this I choose not too. Is there a way to jump the relay? Or how do I check the socket the relay plugs into? I have my console off and have checked all the wiring and can see no issues. Any clue on what to check next or how to fix this issue? Console off to replace radio and to install Dave's new led panel on console panel. Radio went well, the led panel is finished but before I reinstall the console I sure would like an answer to the blower issue.
Andy B 03513

[djdogbone]

If you are getting fan in 3 but not 4, that is odd. Speeds 3&4 I think are the same relay. It sounds like the actual switch- maybe the wiring AT the switch is the issue.

[DMCMW Dave]

If you are getting fan in 3 but not 4, that is odd. Speeds 3&4 I think are the same relay. It sounds like the actual switch- maybe the wiring AT the switch is the issue.

Replace the switch.

[djdogbone]

I think he had the issue before and did replace the switch but it had no effect, is that correct?

And are you saying the fan does not blow or is there just no air? No air but a running fan is a vacuum hose issue at the switch

[Bitsyncmaster]

There is a relay for fan speed 3 and another relay for fan speed 4. You can install a jumper into the #4 relay socket to test the output wiring. If your speed resistor was shorted you would not hear a speed change from 3 to 4. My schematic shows two wires on one side of the fan circuit breaker but not sure if that's the junction for the power for 3 and 4. The jumper test should help you find the problem.

One thing that can happen is the relay sockets can get mounted in the wrong places (my headlight sockets were swapped). Best to lift the relay bank and verify all the pins are seated and correct wire colors.

[hmcelraft]

Fan speeds 1 and 2 run directly from fuse 10 through the resistor module to the fan. Speeds 3 and 4 have primary power from the circuit breaker to separate relays for each of speeds 3 and 4. Speed 3 relay is activated by power from fuse 10. Power for speed 3 is from a relay to the resistor module. Speed 4 relay is activated by fuse 10 power but is WOT from the relay directly to the fan. You can see how the fan switch directs this on page M:18:19 of the service manual.

Since you have changed the switch, I would suspect you have an open circuit on speed 4. --------- From the circuit breaker? A relay connection has been pushed down out of the relay plug? Open wire to the fan? Speed 4 connection on the switch is not complete or open?

[andy blackmon]

Thanks to all of you guys , between the clues you gave me and a little luck I found the fan speed 4 issue. The was a wiring problem in the relay department that needed to be repaired now all 4 speeds work. Thanks for the help.
Andy Blackmon 03513