Cab blower motor

[patmlem]

I have a 2008 S250 I've had for a few years. The fan switch never worked but recently decided to try and diagnose the issue. The switch itself doesn't get power. The fuse is good. I found a relay under the cab that looks like it runs up to the blower. It has 1 red wire 1 black wire and 2 orange wires. If I jump the orange wires together the fan kicks on and switch operates as it should. I replaced the relay with a new one and still doesnt work. Is there a inline fuse or gound that may be open? Whats the wiring diagram look like for this circuit?

 

[fortworth-cowboy]

I have a 2008 S250 I've had for a few years. The fan switch never worked but recently decided to try and diagnose the issue. The switch itself doesn't get power. The fuse is good. I found a relay under the cab that looks like it runs up to the blower. It has 1 red wire 1 black wire and 2 orange wires. If I jump the orange wires together the fan kicks on and switch operates as it should. I replaced the relay with a new one and still doesnt work. Is there a inline fuse or gound that may be open? Whats the wiring diagram look like for this circuit?View attachment 8891View attachment 8892

Do you have a Serial Number and Model Number?

 

[patmlem]

Do you have a Serial Number and Model Number?

5213122 series and S250 model

 

[patmlem]

Ok I figured out the problem and it wasn't easily seen. I pulled the fuse block out and saw someone bodged in inline fuse. Red wire 1140 was getting 12 volts from this fuse but I wasn't getting power at the relay under the cab. Wierdly enough I was getting continuity which made no sense at first. I looked at the big harness connector on the right side and tugged at 1140 red wire. It easily pulled out of the connector and was completely corroded off. I removed the bodged "house" wiring they used and just bypassed the bad connector with the inline fuse.