no power to blower...advice needed...

[flathead31]

in short my truck was stolen in the day time...after a month, i get a call, they pulled a guy over in it, he had a warrant...so i went and drove the truck home...iam grateful and lucky...more to the story later..here is the issue. i notice that the fan only worked on hi, after looking into it he had the resistor unplugged because it got hot and melted the mounting it was in, also the dash was trashed.. he didnt know how to take it apart to put in the new heater core..but he got in installed...so i replaced the trashed, air plenum box that has the heater core, ac coil and blower motor. as well as the whole dash assy, after the complete reinstall, i replaced the blower motor and resistor,, no blower...fuse at the fuse panel is good, and the fuse under the hood is good as well as the blower relay...also new ignition switch...i did find the heated mirror wires from the push button on the dash had melted and burnt some wires i traced and seperated the ones that were stucked togeather ...here the thing if i run a hot wire a spot on the blower relay plug, fan works on all speeds, seems i lost power from some where there lies the problem..

 

[flathead31]

anyone know where the blower relay gets its power from, and does it have anything to do with the heated mirror wiring,,,

 

[flathead31]

anyone?

 

[csuder99]

Fuse 2 in the "junction block" (the fuse panel on the left end of the dash) powers the relay control line and the heated mirrors.

 

[flathead31]

Fuse 2 in the "junction block" (the fuse panel on the left end of the dash) powers the relay control line and the heated mirrors.

thnk you for the reply... do you know what wire color from the blower switch that goes to that fuse....if i power the blower relay plug at the pdc the blower runs with all speeds, seems its from the fuse to the blower switch thats missing...

 

[csuder99]

None. The blower switch is on the load side of the relay and switches the different taps of the resistor block. The control side of the relay gets powered when the ignition is on. The wire between the fuse block fuse 2 and the relay in the PDC should be dark blue. The wire from the ignition switch to the fuse block is listed as black/orange. I'd check both if there's 12V present with the ignition turned on.

 

[flathead31]

None. The blower switch is on the load side of the relay and switches the different taps of the resistor block. The control side of the relay gets powered when the ignition is on. The wire between the fuse block fuse 2 and the relay in the PDC should be dark blue. The wire from the ignition switch to the fuse block is listed as black/orange. I'd check both if there's 12V present with the ignition turned on.

i will check thanks again...will that be 12v grounded to the chassy?

 

[csuder99]

12V measured between the wire(s) and ground, yes. You don't want to short 12V to ground ...

 

[flathead31]

on the back of the switch the is a long skinny plug, and below that plug is a small plug with three wires, dark blue, blk with a orange stripe, and a light blue with a yellow stripe, the light blue wire with the yellow strip is the one that i found melted through the wiring harness...in the process of seperating the melted wires i just cut the three wires,,,thinking they are just the heated mirror wires...help lol

 

[csuder99]

Yes these are the heated mirror wires. Does the dark blue one have power with the ignition on ? That's the same dark blue that also powers on the blower relay. I'd think if there was some sort of short it probably blew the fuse so if there is no power on dark blue double check the fuse, then trace the wiring especially around the fuse panel. The cut wires don't affect anything else besides the heated mirrors not working.

 

[flathead31]

no power on the dk blue wire,,,,the only power is on a thin green wire on the long plug...so none of the three wires on the small plug will effect the blower? is there any way to put a fused wire to witch ever wire the works the blower relay? as i said i can put power to the relay plug number 87 on the relay the blower works on all three speeds..wanting to fix it without pulling the dash again... btw thank you for the help...

 

[flathead31]

iam hoping this plug goes to the pdc under the hood, and i can find the trigger wire or wires that will work,,,but have no way to know lol

 

[csuder99]

Not a fan of "creative wiring", it can cause more issues and worst case the truck catches fire. You would still need to find a switched 12V source so the blower stops running when the engine is off.
Try tracing it from the other end: Check fuse 12 in the PDC, this fuse powers the blower motor when the relay is on. I'd guess it's ok from your description but I'd still check. Also check fuse 2 in the PDC, this fuse powers a number of things in the fuse panel via the ignition switch. Fuse 2, 3, 7, 18 in the fuse panel all get power from fuse 2 in the PDC. Check for power on all of those with the ignition on. Ideally you have a test light or multimeter with a small enough tip to touch the exposed test points on top of the fuse so you can leave the fuse in. Check both ends of the fuses. It would be really weird if fuse 2 receives no power but the other ones do, that would be a failure inside the fuse panel.

 

[flathead31]

i agree about creative wiring.....i have power on all thoses fuses...thats such a pain to take that dash back out...is that plug in the last pic, the conection to the pdc? i was hoping to find the wire that needs power to switch on the relay, and just run a proper sized and fused igntion power source...but i want it safe...

 

[flathead31]

iam hoping this plug goes to the pdc under the hood, and i can find the trigger wire or wires that will work,,,but have no way to know lol

View attachment 154903

is one of theses wires if so witch one...turn on the blower relay....

 

[csuder99]

That's not the right connector, there's a very large black one with 74 pins between the inside and the engine compartment. The easier access is on the back of the fuse panel. Towards the rear of the vehicle is a connector with only 4 wires. The bottom 2 are black/orange from the ignition switch and dark blue towards the blower relay and the heated mirrors. If the connector is looking ok and there's no power on dark blue right there then I'd say the fuse panel or "junction box" is at fault. (Again, be certain there is no issue with the fuse or socket in position 2) In this case you could put a fuse between the two bottom wires to get fused power to dark blue wire.

 

[flathead31]

 

[flathead31]

here is a pic i found not seeing the drk/blu or blk/org...

 

[csuder99]

It's the large white connector with only 4 wires on the right of the last pic. I do see dark blue in pin 4, the pin next to it should be black/orange but hard to tell.

 

[flathead31]

It's the large white connector with only 4 wires on the right of the last pic. I do see dark blue in pin 4, the pin next to it should be black/orange but hard to tell.

i will ck it out thanks again......so if i power the dark blue it should trigger the relay ?