Blower Help!

[GsxrMike]

Ok i've traced down where I don't have power going to my relay. The red wire all the way to the left has no power going to it with the blower set on high. I am sure this is my problem but what I don't know is where the power for this wire comes from. Would not having power on the red wire cause my blower not to work in any speed? Does anybody know which fuse runs the blower. My big ass has a hard time getting up under there to pull the fuses (6'4" 290lbs). I pulled a couple but they were fine and then I had to take my son inside because he is sick. I had 12VDC on the orange and blue wires and the relay is working fine. If I ran a inline fuse from the distribution block on the firewall to the large red wire would my other speeds on my blower work? What gage wire would I need to use? And finally...I am suppose to have voltage on all of the wires going into the back of the resistors when set on high? TIA!

 

[4X4HIGH]

I'm assuming you're talking about a heater blower motor? Not sure what year you're working on but IIRC there is a rheostat that controls voltage while on the HI setting and if that rheostat goes bad then you'll have all other speeds except HI. The rheostat is located on the suitcase under the hood.

 

[dyeager535]

Whoops, posted in other thread, will keep it to this one.

Don't think there are any fuses. Not sure how the relay is setup, but I'd think that one of the wires to the relay should be hot with the key on, likely the red one.

 

[GsxrMike]

'86 K5 Blazer. I didn't know there was more than one blower? I have no blower on any speed although I have voltage going to all of the resistors and my relay is working. Blower works as well when wired direct.

 

[dremu]

You don't say what year, but there's some quickie electrical diagrams on the Brochures site which should get you closer.

Looks to be mostly the same for all years...

http://brochures.slosh.com/wiring/70 - 76 Chassis.pdf

the center section at the bottom is what you're dealing with, and it claims there is a fuse.

http://brochures.slosh.com/wiring/86 Chassis 1.pdf

at the top, looks like a different arrangement of the same.

http://brochures.slosh.com/wiring/

has the lot.

-- A

 

[dyeager535]

Must have changed later, since that doesn't show the relay.

I'd really expect the relay to be for "high" only. Maybe there is a fuse, but I don't recall seeing one. Best to check the panel in that case.

Only one blower.

Are you saying that in other than the high or off positions of the switch (not the slider) the respective resistor is getting power? Essentially there is one resistor for each fan speed. The switch sends power to the correct resistor based on it's position. So only one resistor should have power at any one time. The "high" position wire should go straight to the blower motor without a resistor.

 

[GsxrMike]

You know I didn't check the resistors with the switch in any other position but I will when my wife gets home or if it warms up outside because my son is sick. What was weird is I was getting power to all of the terminals on the resistor plug with the blower set on high.

 

[dyeager535]

That SEEMS odd, but really wouldn't matter, since the fan needs 12V on high. With power to all resistors, AND a direct 12V wire with no resistance for high, the fan will get what it needs.

I don't think any of the resistors NOR the 12V wire should get power if the fuse or switch is bad.

I'd have to look at a good diagram, but I expect that since the blower motor only has one wire going to it, that's the "output" for all resistors and the 12V high lead, so you'd need to look at power TO the resistors to make sure the switch is working right, and then work out whether the resistors are all bad.

 

[GsxrMike]

I am going to run to Advance and get a Haynes manual in a bit. The red wire wouldn't have come off of the distribution block would it? I know we gutted alot of wiring during the build.

 

[dyeager535]

It could I suppose. I don't know as I'd buy a Haynes until I opened it up and made sure the wiring was identical to yours. They are pretty poor in some regards. Better than nothing, but awfully generic as far as year differences. AC vs. none is a pretty big deal though, they should show that.

All the ones in the local stores are wrapped in plastic so you can't look at them.

 

[Wrench]

The fat red wire comes from the dist. block on the firewall.

 

[GsxrMike]

The fat red wire comes from the dist. block on the firewall.

I thought that might be where it came from. Does it tie into anything else or is it a straight run from the dist. block to the connector? Thanks!