Cape Fear Electronics

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The hazard switch has more conductors (9). The previous version plug used smaller terminals. Maybe this was a way to get a larger terminal surface in a reasonable space? SAE J910 requires testing with max bulb load (without flasher) over a temperature range. Did the hazard lights change in 73, resulting in a greater load on the switch and connectors? Just guessing.
 
The hazard switch “waffle” type connector was used from 9/72 -8/77. You’ll notice the switch side connector has 9 pins but the harness side had only 7 from about 12/74 - 8/77 when they changed to an updated switch/connector and pin configuration.

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The reason the 1975-77 harnesses only had 7 pins when switch had 9 pins was Toyota redesigned the circuit to save money on copper. A single pin now controlled both front and rear lights on each side. A consequence of this is sometimes a burned melted pin on the Hazard switch connector due to the single pin driving TWO lights causing overheating of the pin..

The pin design must be load related. In my view, the hazard switch is the most complex circuit on our 40’s.
 
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Ackcruisers said:
Nice vintage wire gauge tool. It looks new.
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Thanks, it was NOS. Starrett made great stuff back in the day. I have a couple 120 calipers too. This one is minty.

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Engineer8000 said:
The hazard switch has more conductors (9). The previous version plug used smaller terminals. Maybe this was a way to get a larger terminal surface in a reasonable space? SAE J910 requires testing with max bulb load (without flasher) over a temperature range. Did the hazard lights change in 73, resulting in a greater load on the switch and connectors? Just guessing.
Click to expand...
Ackcruisers said:
The hazard switch “waffle” type connector was used from 9/72 -8/77. You’ll notice the switch side connector has 9 pins but the harness side had only 7 from about 12/74 - 8/77 when they changed to an updated switch/connector and pin configuration.

View attachment 3824628

The reason the 1975-77 harnesses only had 7 pins when switch had 9 pins was Toyota redesigned the circuit to save money on copper. A single pin now controlled both front and rear lights on each side. A consequence of this is sometimes a burned melted pin on the Hazard switch connector due to the single pin driving TWO lights causing overheating of the pin..

The pin design must be load related. In my view, the hazard switch is the most complex circuit on our 40’s.
Click to expand...


.

- the same production date-year spac. a FJ55 has the same circa era waffle-connector HAZARD switch , but it has a 10 wire configuration , as in all 10 connector bays are occupied , it is NOT a 9-wire HAZARD .....


Any ideas what for / the why factor here Russ or mr Paul ?

.

.

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Sorry, Matt, I can't find any reference to the 10 wire FJ55 configuration in either the parts fiche or EWD. Do you have a picture of the switch/connector wiring, it may give a clue.


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I have been working out my 3FE check engine light (CEL) circuit. In the FJ62 the ECU provides the ground for the CEL, the power is from the "Gauge" fuse

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The issue with this is the bulb has to be isolated from ground. The two styles of bulb holders used for the FJ40 dash lights are:

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The one on the left is isolated from ground, the one on the right isn't. The mounting of the light holder provides the ground for the bulb circuit. The problem I have is I have two NOS holders like that on the right I would like to use. I cannot use this out of the box for the CEL since the ECU provides the ground for the CEL circuit. This means I need a way to switch a bulb on and off using the ground of the ECU to pick up a relay and use the contact of the relay to interface with the CEL holder.
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But, I cannot use a relay that overloads the ECU CEL circuit. I took the cover off a spare ECU I have and found the CEL is controlled by a Darlington pair transistor, 2SD1491.

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I found an old NEC transistor databook using the wayback machine.

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The 2SD1491 is rated for 1W without a heat sink, so assuming 13.8 VDC, the max C-E current will be 72mA. I have some of these OMRON G5LE-14 relays that have about 40 mA coil current. I think this will work ok without overloading the ECU CEL switching transistor. The 2SD1491 is designed to drive the solenoids in the old line printer print heads and has a built in "dumper" diode. I learned this to be a flyback or freewheeling diode, I have not seen the dumper term used before. Driving a small relay should not be a problem for this transistor.


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@Engineer8000 the term “dumper diode” is new to me. It’s essentially a flyback diode then?

Tangent story: I used one of the grounded 40 Series turn signal lenses as an on/off indicator in a guitar pedal I built. It’s a tremolo circuit and the indicator light (a diode secured behind the 40 Series lens) flashes in time with the tremolo rate. These things have other uses!

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Ok, carry on!
 
Engineer8000 said:
I have been working out my 3FE check engine light (CEL) circuit. In the FJ62 the ECU provides the ground for the CEL, the power is from the "Gauge" fuse

[A
Click to expand...


1




If you get a new BA9 bulb & remove the glass globe

Mix-up some fast-cure JB weld and cue-tip the inside area that you have now freed-up on any solder , or conductive material . It’s an open bowl ….

🥣 Good-Nice skim kote it maybe 2 applications, now you have a pre-insulated BA9 “ dummy-socket of sorts …

make-sense Russ ?

, then arrange your 3 leads / conductors in a pattern that avoids contact with the brass / tinned housing …

The 2 bayonets will engage in the socket , that now will press-click during the chrome lens bezels ..

Remember : the lenses are simple old age and time KOITo plastic cast resins ,

NOT glass like I once thought 💭 they were ..🤔

I have successfully applied “ NU-FINISH “ the little orange plastic bottle with black writing , to a good quality cotton ONLY cue tip , low speed drill or dremmle tool on LOW only , plenty of liquid nu-finish , do NOT let it heat up or the little baby KOITo will see a fast and certain Doom …

After you polish out to where the nu-finish begins to dry do to the H2O & Solvent blend liquids evaporate ….

STOP ,🛑 let it dry first a while till both completely dry and cool to the touch , the cue tip by finger tips only …

I emphasize the heat / BTU factor here because I had toasted more then a few to
get to the sweet spot inside and outside each lens …

It was a total brown-frown to find out they were not JIS Colored Glass many years ago …😕

But now we know and NU-FINISH is the way …


Hope this helps Russ ..,
 
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This is what I ended up with for my CEL. I had a few 2SB536 PNP transistors in the drawer, so I ditched the relay idea. Just ground the base of the B536 via the ECU and the light comes on. A little over 4 mA current on the 2SD1491 in the ECU.

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