Hope someone can help me here.
My son has a 1980 yota truck with a parasitic draw that I have narrowed down to the brake circuit. I have disconnected the main wire from the battery to verify my problem. Wire off, no draw but also no brake lights. Wire on, brake lights on, and 1/2 milliamp draw on battery.
So my question is, has anyone had a similar problem and can someone tell me where to find a better wiring diagram than what I have. Mine seems to show that the taillight relay is connected with the brake light circuit, which makes no sense. My problem should be forward of the brake lights as the brake switch should prevent power from going any further. So, unless there is an additional wire that someone tapped in to the system for which I haven't found, I don't know where else to look.
I guess I really just need a good wiring diagram to go by.
And no, the brake lights don't come on without applying the brakes. Which is why this is puzzling me..

Thanks in advance for any help.

 

The FSM is really great for these vehicles. A necessity if you plan to do much work. They have good wiring diagrams.

Hopefully someone will be able to answer your question better, but I do know that you never know what someone might have rigged up in a truck this old. I've run into some crazy stuff with my truck...very frustrating.

 

free fsm download here

http://www.ncttora.com/fsm/

wiring diagram should be near the end

 

No, no lights without foot on pedal. That's a why I am puzzled.
Thanks.

 

I've reread this a couple of times and I have a question. Is the battery going dead overnight or are you seeing/measuring a 500 miliamp usage when you step on the brakes?

 

No, it takes about 2+ days as it is about .5 milliamps draw that is constant. The lights all work normally, but the draw is from that circuit.

 

That FSM link probably isn't any good for your truck, so ignore it. Unless something has changed in the last 6 months, there is NO online FSM for our trucks. They didn't make a 79-85 FSM. They made one for each year. The first available online FSM is 1984, but for some reason whoever posted it chose to name it 79-85. It is NOT the correct FSM for any truck between 79-83. I know it's typically different people so I won't be harsh, but I get annoyed at all the non-First Gen people who post that link in the pre-84 section. It's not accurate.

Just start looking for a used hardcopy. You'll be glad you did.

 

Well, If you look at the title, as you said, its posted 79-85, we all know that the 79-83 was a differant truck then the 84-85... But This is a site to try and help people out, the link was posted to help someone. My appoligies it wasnt accurate, I didnt down load the 79-85 one as I dont have a truck that year.. O HOLY YOTA GOD Please for give me!!!!

and a side note, your 83 is actually a third gen truck, however its a first gen 4x4 (if were going to be picky about things)

 

No, it's fine to try and help. But things changed so much throughout the years that I don't think he wants to be looking at an 85 FSM wiring diagram to chase down the problem in his 1980 truck. They're confusing enough as it is, when they're the right diagram.

Sure, you can come in the pre-84 section and split hairs on "first gen" all you want. It's been covered here. Years ago. It's understood, among most Toyota owners, that when we say first gen, we're referring to 4wds.

Anyways, yes, this site is to help people. I appreciate that you're trying to help, but just like what's happened to me in the past, you know what they say about good intentions...

Fact is, that FSM link is not helpful if the OP doesn't know that the FSM is not for his year truck. Could be hurtful. I've given well meaning, bad advice in the past. I swallow my pride and move on.

Yes, without downloading it you had no way to know. Like I said, it's usually different people posting that link, because they usually only do it once before they learn that it's no good for our trucks.

 

10-4 Good buddy.................

 

I don't quite understand this comment.
Is it because pre 79 hilux didn't have 4x4?
And I thought mercedes guys were bad lol.

 

Yeah...

It's not a hair I care to split, unless someone else brings it up. But through the wisdom of the internets , I've found that we call our trucks (79-83) "first gen". Every now and then someone asks why, since there were previous generations of Toyota trucks, cars, land cruisers. That's probably why the title of this area is "pre-84", rather than first gen. But it seems to be understood that if you call your truck a first gen toyota, you mean 79-83 4x4. First generation of Toyota 4x4 trucks. So it's only really ok to say first gen in the right company...like among toyota 4x4 truck owners. Otherwise, it doesn't have much meaning, and isn't really accurate.

Beleive me, any group of people who get into any vehicle (or anything at all, for that matter..), will "geek out", so to speak, on this type of silly stuff.

 

By the way, I'm not trying to be an ass, but that link is kind of a pet peave of mine. It's like the "what size tires will fit on my IFS truck" threads...even though it's always different people, you can only see that question so many times before you start being a little rude to the poster...

 

yup totally understood. we'll leave it at this.