XR7-4.6’s disjointed build thread 2 Electric Boogaloo

[Kenz]

This time I will be converting auto to manual without altering a single thing in the existing wiring harness, not a cut, not a splice, nothing. The name of the game is plug and play. That is the challenge I have created, and I accept the challenge!

So your car had manual climate control, you swapped that to the semi-auto setup, and now you are swapping it back to manual climate but using the auto climate control harness and parts?

 

[Grog6]

I thought it meant harness swap. IIRC, you have to add wires to go satc, so if Matt isn't altering; he's going back to original config, by unplugging the current one, and putting back the og stuff.
Am I even close?

 

[XR7-4.6]

It has a SATC harness in it now, and it will remain. The TLDR is I’m not changing the dash harness to reinstall manual climate control but also not altering the harness it at all, I’m building a plug and play setup to work with it, so it’s reversable if I wish

 

[Grog6]

Makes sense; I'd agree keeping all options open is best.

 

[KevinVarnes]

Eagerly watching this as I would love to switch from the auto climate control to a nice old fashioned manual version. All of the cars that I see in junkyards have the auto version.

 

[1997ThunderbirdLXV6]

All of the cars that I see in junkyards have the auto version.

I definitely see a good mix. More manual A/C on later years.

 

[XR7-4.6]

I’ve found the vast majority of 94-95 V8 Thunderbirds have auto, where 94-95 Cougars and 96-97s across the board are more mixed in equipment

 

[Grog6]

My 97 le had no options exc power drivers seat, and the spoiler.

 

[XR7-4.6]

My 97 le had no options exc power drivers seat, and the spoiler.

It has more than you think, believe it or not stuff like power locks, rear defrost and cruise control were all options, but the V8 group automatically included those, including power driver seat. There wasn’t any true Roadrunneresque stripper V8 combination you could order for these cars… unfortunately because that would be really cool!

 

[XR7-4.6]

Alright blend door (and illumination)harness done



The big black connector will actually plug into the SATC connectors… it’s actually salvaged off of a dead SATC head… I was hoping to get more outputs from it but as it turns out of the 48 pins in it you only actually need 2! Ignition power and ground. The temperature knob has 3 wires and is wired straight to the blend door, the power and ground powers the blend door actuator (it basically functions like gauges). Only other useful thing in the harness is illumination, you can’t use SATCs illumination wire(LG) as it is not 12v, that needs to be sourced from elsewhere(stay tuned), ground however I shared with the blend door pin.



This wiring is for the blower motor/speed control 6 wires total, and I even color coordinated them!

Brown is source power, wire is 12 gauge, which will be taken from the dash connector that goes to the PWM which will now to the function selector switch, from the function selector switch will be the blue wire(also 12 gauge) and it will run to the blower motor connector. From the blower motor connector is the orange wire(again 12 gauge) which will run both to the resistor block and fan speed knob. Black as you might guess is ground and yellow and green are the middle two speeds between the resistor and switch, these all step down to 14 gauge as per factory spec

The bulk of the work is done with these I just need to cut the blower speed harness to length and solder its source and resistor connectors on. Nice and tidy so far.

 

[Grog6]

I'm curious, are the blower motors the same?
What size is the resistor on that one?
The module on the satc is either a current limiter or voltage regulator; I haven't had one fail, although I killed a blower motor in Lazarus.

 

[XR7-4.6]

The motor is the same, speed is controlled either by physical resistors with the manual unit, or a separate pulse width module controlled by the SATC head

 

[Kenz]

The motor is the same, speed is controlled either by physical resistors with the manual unit, or a separate pulse width module controlled by the SATC head

How are you controling the fan speed with the manual climate control blower motor switch? I would assume that the auto climate control has some sort of PWM signal output? Or is that built into the PWM blower control speed module?

 

[Grog6]

Old school designs either use a dropping resistor OR multiple windings, like our radiator fan. Newer designs use pwn, as it wastes less power.
The Cobra fan I have uses a dropping resistor.

 

[XR7-4.6]

Yep, the manual uses a dropping resistor, with the first three fan speeds tapped into different sections of the coils to achieve different speeds.



When these fail you can still use the fan in high speed, when the auto PWM fails the whole systems dead

 

[Grog6]

That has got to be the cheapest 50W+ resistor I've ever seen! Any chance you have a ohmmeter that can measure that low?
For future reference, you can buy that wire on MSC.

 

[XR7-4.6]

That has got to be the cheapest 50W+ resistor I've ever seen! Any chance you have a ohmmeter that can measure that low?
For future reference, you can buy that wire on MSC.

The total resistance is 2.3ohms, which is low speed. Medium 1 is 1ohm and medium 2 is .5ohm, and high bypasses the resistor so the full 12v powers the fan

It’s constructed like any other blower resistor used in older cars, here’s one from a 60s Tbird



The genius of these things is they’re placed right below the fan blade so any time it’s in operation the fan is keeping it cool