Rear heater switch

[aktundra]

Has anybody figured out the wiring for the rear heater switch?

I can get the dash light to work and I can get the wires for HI & LO.

But I cannot get the diodes to light up with the HI/LO

Has anybody figured out how to get the HI/LO diodes to light up when the switch is . . . . . . .switched?

The top two wires seem to be the dash pos/neg. The unlabeled yellow wire may be another 12v, but I just cannot figure out how it comes into play. It seems like diodes never burn out, so they must be good.

When I disassembled the switch there was a resistor on a little circuit board. Can I put 12v directly to the diode wires to test them individually?

Any suggestions ? I couldn't pull anything useful out of the archives.

 

[NLXTACY]

um am I accurate in guessing that you are using this for something OTHER than a rear heater switch?

 

[aktundra]

yup.

I am going to try and use it as a dual battery combine-auto-separate switch.

I currently have generic black rocker switch on my dash. Once I understand how to get the rear heater switch to behave, I will pull the current switch out and see if I can transfer the wiring over (or take it to some professionals!!)

Either way, I need to understand the rear heater switch.

 

[NLXTACY]

Well every switch I ever figured out I pretty much already have a write here somewhere. The heater switch was not one of them. BUT I will say that with a 12v source and a volt meter it does not take long to figure it out.

 

[NLXTACY]

This should solve it

http://www.vmrdesigns.com/downloads/heater.pdf

Let me know if you have any questions.

 

[wearsabrowncoat]

It would be nice to have all Toyota switches mapped out like this.

 

[gotmud]

It would be nice to have all Toyota switches mapped out like this.

It's called an EWD.

 

[aktundra]

I am just a simple man.

I don't understand most of this stuff. Are the diodes really sensitive ?

I just have a battery in a box sitting on the floor, a little circuit tester that lights up when it has current. I just poke wires one at a time till I get things figured out.

I got the switch out of a '91 in a junk yard. I suppose it is possible that the diodes were burned out before I picked it up. But I thought diodes lasted forever. Are they sensitive enough that I blew them out poking wires with 12v ?

Like I said in my first post, I have the flow mapped out, but I just cannot get the diodes to light up.

Can I disassemble the switch and put 12v & GND directly to the diodes leads just to test that they still work ?

 

[NLXTACY]

Um did you check to see if the bulbs are even good? I wanted to throw one switch away because I couldnt get it to light up until I looked and saw a burned out bulb.

 

[cruiserdan]

The hi-lo indicators are LEDS and are driven by a switched ground.

 

[aktundra]

I am not so much worried about the dash bulb. The HI/LO lights are diodes

Here are the parts of the rear heater switch (except the dash bulb !!!). The LO lens is laying in front of everything.

There is a yellow & green diode on extremely long leads that provide the light for the HI/LO lenses.

The diodes are soldered into a little circuit board, so they are not designed to be replaced like a bulb. So they must never "burn out" under normal operation. I am just wondering how sensitive they may be when some idiot is poking wires directly to the battery.

 

[Trailbus]

I used that switch to run my electric & engine mounted air compressors. You probably just need to unsolder & turn the diodes around. you can check to see if they are good by using an ohm meter, one way should show an open circuit & when you check the other way, it should indicate less resistance (indicating current is flowing).

Current should flow in the direction of arrow symbol (which would be from positive to negative)

I had to switch my diodes when I was using the switch to control the grounds to the my relays. When I later rewired to switch the positive side of the relays, I put it back to original configuration.

Greg

 

[gbell210]

Yea.. its been done before with detailed pictures, multiple ways:

https://forum.ih8mud.com/80-series-tech/148815-rear-heater-switch-pin-out.html

 

[aktundra]

at the risk of hi-jacking my own thread.

How come I cannot go to advanced search , and type in "rear heater switch" (no quotes) and pull up the thread gbell210 posted the link to ?

Thanks gbell210, exactly what I was looking for.

 

[medtro]

at the risk of hi-jacking my own thread.

How come I cannot go to advanced search , and type in "rear heater switch" (no quotes) and pull up the thread gbell210 posted the link to ?

Thanks gbell210, exactly what I was looking for.

Try select Search Titles Only after you type in "rear heater switch" (no quotes).

 

[TomH]

Here's another one.

https://forum.ih8mud.com/80-series-tech/35679-dual-battery-w-pic%92s-verbose.html