Deciphering wiring diagrams? (1 Viewer)

[fireball]

Guys,

Hopefully someone can help me out. I like to consider myself a reasonably intelligent guy, but the LC wiring diagrams have me confused. I've got a bunch of switches I need to wire up and have all the new wires coming into the cabin at the appropriate places. I was able to get a 2 day subscription to the Toyota website where I could download various pages of the 1999 EWD.

Here's the first question:

Please see attached photo of the seat heater switch wiring diagram. The diagram shows 4 wires coming out of each switch. It doesn't seem to show the dash illumination wire coming in.

Please see photo of actual switch which has 6 wires. What am I missing??

 

[spressomon]

For whatever reason the switch light is not shown on the seat heater switch diagram but yet another page on the EWD as a separate circuit. Do a PDF search using "seat heater illumination" as your search criteria and it should bring it up.

AFAIK the triangles with the arrows pointing away are the LED lamps (for the two heat levels). Whereas the switch light has a filament type bulb...as indicated on the separate EWD page.

Maybe someone a few pay grades above me will chime in

 

[yotasavg]

Funny that you post this... I printed out a few pages of the EWD yesterday at work and they're now layed out like a puzzle on my kitchen table. I'm reading about the wiring for the rear AC circuit and all that's been accomplished so far is I've scratched my head a lot. I wish you good luck, and I certainly hope a wiring guru can tell us laymen how to begin reading these docs (yes, I read the "how to use this" section at the beginning).

Oh and I'll second what Spresso said, I managed to waste my time flipping through the whole EWD because what I needed was at the very back. There is indeed a separate section on different illuminations on the dash which should have what you're looking for.

 

[PADDO]

For whatever reason the switch light is not shown on the seat heater switch diagram but yet another page on the EWD as a separate circuit. Do a PDF search using "seat heater illumination" as your search criteria and it should bring it up.

AFAIK the triangles with the arrows pointing away are the LED lamps (for the two heat levels). Whereas the switch light has a filament type bulb...as indicated on the separate EWD page.

Maybe someone a few pay grades above me will chime in

'Spresso's correct, Toyota's methodology breaks their EWDs down to the system level and differentiates function groups - in this case we have two things going on; "illumination" and "seat heater". One switch, but two functions.

 

[TexasCharley]

Thank God someone else is asking this question. Suuuubscribed!

 

[hankinid]

It baffled me at first, but it's actually easier to understand. Think what the wiring diagram for the seat heater or, even worse, the headlights would look like if illumination info was overlaid on the heater or lights diagrams.

 

[fireball]

Thanks for the point in the right direction. I've attached a copy of the illumination diagram page.

Looks like we have a Green and a White-Green wire coming into the switch for illumination purposes. Can I tell from the drawing which one is 12v and which is ground? It's raining and I don't feel like going outside now, but this should account for the 6 wires.

Green (illum.)
White-Green (illum.)
L-W (power in)
W-B (ground??)

DS:
B-R (12V out to low setting)
R-G (12V out to high)

PS:
B-L (low)
R-L (high)

Let's hope those colors match up with what's actually in the truck!

The new replacement seat heaters I installed with my new leather covers have a simple 3 wire switch. 12v, Hi, Low. So I will cut the high and low wire and which 3rd wire? the L-W?

Thanks!

 

[yotasavg]

From looking at the diagrams I'd say I agree and you'd need to tap into the L-W for your 12v in, and then the Hi/Lo outputs like you said.

So you're using aftermarket heaters, but trying to wire them to the stock switches, instead of whatever was supplied with them?

 

[PADDO]

Thanks for the point in the right direction. I've attached a copy of the illumination diagram page.

Looks like we have a Green and a White-Green wire coming into the switch for illumination purposes. Can I tell from the drawing which one is 12v and which is ground? It's raining and I don't feel like going outside now, but this should account for the 6 wires.

Green (illum.)
White-Green (illum.)
L-W (power in)
W-B (ground??)

DS:
B-R (12V out to low setting)
R-G (12V out to high)

PS:
B-L (low)
R-L (high)

Let's hope those colors match up with what's actually in the truck!

The new replacement seat heaters I installed with my new leather covers have a simple 3 wire switch. 12v, Hi, Low. So I will cut the high and low wire and which 3rd wire? the L-W?

Thanks!

For illumination Green is +12V and it goes to pin 1 of your switch, White-Green is chassis return, Pin 2. Section M of the EWD are the cct wiring diagrams, these colored cct pages are more flow diagrams and are best read in conjunction with the cct diagrams, makes it a bit easier to follow, at least that's what works for me. The preceding page has the info on it that identifies where the +12V originates.

 

[fireball]

From looking at the diagrams I'd say I agree and you'd need to tap into the L-W for your 12v in, and then the Hi/Lo outputs like you said.

So you're using aftermarket heaters, but trying to wire them to the stock switches, instead of whatever was supplied with them?

Thanks. Please don't be offended if I ask for another set of eyes to confirm this! I don't count myself as an intelligent response, so right now I think you're the only one

Yes, I've got aftermarket heaters but want to retain use of the OEM switches.

I've got rock lights and a rear fog light that I want to wire to SPDT switches (manual on/Off/ on with reverse lights or courtesty lights). Also need to wire the compressor switch. That will complete the current wiring exercises!

 

[yotasavg]

Well.... I wouldn't count my response as one of an expert lol. But I'm 99% sure you and your truck won't blow up, so let us know how it goes!

 

[Sandroad]

Here's something that helped me with the EWD.

http://www.autoshop101.com/forms/h09e.pdf

 

[spressomon]

^ super Sandroad!

 

[yotasavg]

Nice, thanks for that link @Sandroad!

 

[fireball]

Sand road - thanks for the awesome resource, that made for some fun reading last night!

Here's tonight Brain Bender: the courtesy lights have constant 12 power but illuminate only when ground is completed.

I was hoping to wire my rear hatch lights with a SPST switch so that I could have them on, off or on automatically with the rear cortesy lights. Unfortunately, I can't figure out how to do this!

I was going to use the same premise with the switch for my rock lights: on, off, on automatically with the front courtesy lights.

Anyone who would be kind enough to help me figure out how to do this would not only receive Internet fame and fortune but a lifetime of my gratitude!

 

[fireball]

BUMP! Can anyone help with the ground triggered courtesy light wiring?>

 

[RobRed]

I got you covered on the lights...

http://tlcfaq.com/main/2012/06/rear-hatch-camping-lights/