Blower Fan stopped Troubleshooting help

[marlon giese]

I've got a problem on my 04 ST as the Blower motor stopped. Just quit. worked one day and did not upon engine start the next day Drove in some rain the night before and went out in the AM and nada.



This is a manual climate system but it has rear air.

Oh, the rear air works still but the front air does not at all.



Well spent a half day doing diagnostics in the 04 ford shop manual "E F G" testing... but never came to a clear answer on what was wrong. Then I discovered the Auxilliary relay box below the air filter box. Did not see anywhere in the owners guide or ford book there was a second box or relay!

I switched the blower relay on the main box with the other one on the aux box and to my surprise, had the 3 lower speeds! I says to self, just order 2 relays and replace them both!



I ordered them and got them a week later, got around to the fix Saturday and plugged them in. Tested briefly by turning the key to run and moving the switch. It all worked! About 1 hour later got in the ST to go to town and no blower fan at all. all speeds dead. I can hear the AC clutch turn on with switch in the right places and the blend doors open but no air moves.



Spent a couple hours more re-evaluating the testing and more time looking for a diagram online! Still nada. Found a ford wiring diagram book and ordered it but won't be here till next week.



Relays okay, Fuses Okay, Resistor OK, Blower motor OK,



The testing in the shop manual points to a relay but its good :throwup:, I have 4 of them now that interchange and have tried them every way possible!



I tested the interior switches last week and they were in tolerance from the book specs too.



Other notes. The relay up top, the power block looks like it has been hot under the relay. Black bakelite turned brown... so I took the power block out 2 weeks ago and the wiring underneath is all super! no apparent loose connections to the 40 fuse or relay. Tested continuity and all good for these circuits.



Took the aux panel off today and it looks great underneath as well.

What the heck?



Anyone got ideas?

Is the lower relay in the aux box for the hi blower? Seems like it makes sense and testing 2 of those leads run to the fan motor. One trips to the the Resistor. I assume one goes to the other relay for main power and not sure about the other 2-3 leads.

 

[Yardsale]

Electrical specter.



Seems like an intermittent bad ground or relay, or a bad connecter?



Bypass the relays.



Does any of this run through the GEM?

 

[marlon giese]

GEM? sorr, don't know that one.

The selector switches for the A/C, Heat and temp do work since the rear air changes, (rear blower fan works.)and the front temp changes which I can feel from the RAM air effect at highway speeds.

Got the wiring diagram and I do think the testing points to the switch. A panel is on order but weather delayed and not here till monday. Hope to try to bypass the switch tomorrow but won't be much over 30 for the day and the truck is outside. Snow cold and wind came in hard today in wyoming! get ready for global warmiing to continue! :smack:

 

[Yardsale]

The GEM is {ready for this?) generic electronics module. All kinds of cra, uh stuff is controlled in this. Great for assembly, but they are expensive and when just one function is bad, it hurts a bit to buy a multi-function module.

 

[marlon giese]

well you all are not going to believe this...



Found the issue after many hours and hours of research and testing. Bypassing relays and switch testing over and over with intermittent results on some of them! Went back to the start. The relay for 123 speed on the main panel near the battery.



I noted the bakelite under the relay was discolored as step 1 but the relay was engaging. I tool the whole main panel off (what a chore) and tested the continuity from bottom leads to top connector for the relay position and the feeds for it. First time 3 weeks ago it tested fine.



Well after no power where it should have been with bypasses, we pulled the main power panel out again. Tested the connection from top to bottom on Pin 30 for the fan relay. It was bad then it was good then it was bad again... We decided to try to pull it out from the bottom and it broke off. Looked like it was arcing and broke already making only intermittent and then No contact. Heating up the bakelite panel while it was arcing. Anyway the darn panel is a pain to work on and I cracked the yellow cover on top getting the rest of the connector out. Once that was done, we crimped a 1/4" female S/S wire connector on the lead and re-inserted from the bottom. Put a little hot glue to hold the connector in more securely. Plugged in the relay, buttoned it all back up and tested. Yipeee! ! have a fan again! :driving:

:banana:



Gotta say the clue was what we first saw with the discolored area around the relay pin 30. Finally with the wiring diagram, the diagnosis and tracking backwards became easier.



If anyone ever wants to take off the main distribution panel, let me know. its a bit of a chore but doable if there is a need!



Thanks for the ideas and suggestions. Tried them all and many more! I guess 12 hours of work is what it took to get it to working again. If I had gone right to the discolored spot, I think its about an hour of work. Maybe 3 wrenches worth!