heater temperature sensor; re-wiring question (1 Viewer)

[DSRTRDR]

early '72 FJ40: Inside the duct from the front heater blower to the cab, there is a temperature sensor which, on the outside of the duct, has a socket with 5 flat blades for a connector to wiring. Anyone have an idea what connector looked like and where it connected? I presume it was going back to something that regulated the blower motor. Specter's diagrams don't show the sensor gizmo, and neither factory nor Haynes manual wiring diagrams have that detail. Any insight is greatly appreciated. Thanks in advance, Claudia

 

[cardinal fang]

Ask, IDave, he has the shop manual and is wealth of info on the stock gizmos.

 

[IDave]

Ask, IDave, he has the shop manual and is wealth of info on the stock gizmos.

May be, but I have never run across this beast! I was gonna see if I could find anything of the sort on my friend's donor 72 at his shop.

But my gut instinct says this isn't stock, or at least not of the 72 era.

Convenient place to put a radio/tape deck wiring connector, though.

 

[DSRTRDR]

Dear iDave,

if you do find it, I would like to know the colors of the wires and which position they occupy in the connector, and which wires connect to the regulator (which I believe is at the side or on top of the blower motor).

The reason I am asking is that a PO replaced the part on top of the blower motor with a VW/Bosch thing whose input socket into the regulator is different; I just want to restore the condition to where the heater blower motor switches off when the air temperature in the duct is sufficient.

If, incidentally, the blower motor would be fore sale, I might consider just buying the whole thing.

According to Specter's schematics on Page 186 of their catalog, they show a resistor (#76 in the Heater Blower diagram) with a wire and connector, but no socket is shown on the duct in the diagram for the 68-73 40 series. The position of the socket on the duct would roughly just beneath the number 16, and the sensor itself looks OEM.

Thanks in advance, Claudia

 

[Degnol]

Claudia, AFAIK, there were no temp sensors in the heater ducts on any FJ40s.
The resistor is just to make two speeds. Low goes thru the resistor and high bypasses it. Basic system, nothing fancy. Maybe you could post a pic, but I'm guessing it's a PO thing. No Bosch, just Nippondenso.

GL

Ed

 

[IDave]

As Ed says, Claudia, you have something non-original. The heater resistor attaches to the heater blower (looks like a handle). No temp sensor in the duct, at least in the 74 and earlier era. Beyond that is outside my baileywick.

In the original, you turn it off when it gets warm (and in an older FJ40, that's not something you need to worry about doing in the winter!)

 

[DSRTRDR]

Here are pics of the gizmo:

this is inside the duct from the fan:

and here are the connectors on the outside:

No idea whether this is OEM but please note the 'Made in Japan' sign. The somewhat haphazard-looking mounting holes/slots would argue against OEM. Then again, it sure looked like it had been in there for a long time.

The gizmo looks to be some kind of heat-sensitive interrupt. Held the heat gun to it while on a test circuit, and it did interrupt - unfortunately, it may be have been a terminal event at this time, don't know for sure, two solder connections came loose, we'll see. Right now we're mainly curious as to what this thing is for - cut power to the blower motor when it's too hot?

In any case, turns out one of the PO's installed a blower from VW/Audi, which happens to be a three-speed unit; PO had only the max speed connected to the heater switch. So we'll use the two positions on the heater switch to control medium and high speed on the blower. Not sure whether we'll have the blower go thru a relay, at least on the high circuit