I am trying to figure out why my blower fan has stopped functioning.

Fan itself is good.

I have taken the entire fan assembly out and tested its parts, they are have proper resistances, continuity. Thermal fuse on back is still good,

If I take the one 5 pin relay off of the blower assembly , and bypass it, by connecting the two thicker guage power wires( Red w white line, Blue) , the fan works as iexpected. The fan slider on the logicon will go to zero, max, and every speed in between as you would expect. So I am thinking that this or whatever controls this is the issue. Using some test wires, the relay bench tests as expected. Using 12v car battery, the relay clicks, but nothing when in the car. Relay works on as low as 7.5 volts with batteries.

I have taken the logicon apart, there is no visible signs of burnt parts, and all resistors are measuring good.

I am unsure what to try to look at next.

Have been using all of these threads, none seem to have my issue.
https://www.rx7club.com/2nd-generati...orking-861824/
https://www.rx7club.com/2nd-generati...rching-866883/
https://www.rx7club.com/2nd-generati...clicks-663123/
https://www.rx7club.com/2nd-generati...blower-231997/
https://www.rx7club.com/2nd-generati...-blows-244038/

 

replace logicon and re-check?

 

Here is a write-up I put together a few years ago. It covers the replacement of the main fan transistor located under the heatsink in the blower unit, as well as the testing and replacement of components in the fan amplifier attached to the logicon. The blower transistor controls fan power at max fan, while the amplifier controls the variable speed portion. Also clean your sliders.

https://www.rx7club.com/2nd-generati...build-1125980/

 

Sadly, I have already done this. I thought I had included it in my links on the original post.

I just had a thought, I am in the middle of re-adding an AC system to the car, and am running a Megasquirt 3 standalone. I have yet to wire the AC to run though the ECU to control AC idle up or even bridge that to just get it functioning, but the blower stopped running as the car was running, would that narrow down a possible failure point? I had the pressure switch and compressor connected with their wires.

https://www.rx7club.com/2nd-generati...2/#post9404233


This is the relay that I can bridge the two wires and then everything works. I can not find what it goes to.

 

According to the wiring diagram, the wires going from the fan amp to the ECU are all inputs for the ECU. The only related output from the ECU is related to signaling your AC compressor on/off at high rev.

 

2006 Express 3500 6L cargo. New blower motor, resistor, harness, 3-dial control panel inside. Still no heat or AC, blower not working at any speed. Blend doors do move, so I THINK? I'm getting good vacuum. Fuses and relays good under the hood. There are 2 fuses under driver`s seat that say hvac and hvac1. they don`t seem to be getting power to them.