Engine Push Start Button Install

[AndrewBird]

why the need for the relay?

Um, which one?

If you mean the one he used in the original post, it's because the pushbutton can't handle the amp draw the starter motor makes.

[e304me]

why the need for the relay?

[AndrewBird]

It's all basic stuff. And I KNOW Luke knows it.

[Doughnut]

Huh?

lol, obviously what seems quite technical to us, is really not that technical at all to you.
Electronics and electronic circuits ftw:)

[AndrewBird]

One of these days you are gonna think too damn hard and your head is just gonna explode.

Huh?

[StereoInstaller1]

Well, if you measured the resistance of the seat heaters and electrical, you could calculate the amp draw.

V=IR

"V" being 12V
"I" being the amperage (current)
"R" being resistance.

One of these days you are gonna think too damn hard and your head is just gonna explode.

[AndrewBird]

Well, if you measured the resistance of the seat heaters and electrical, you could calculate the amp draw.

V=IR

"V" being 12V
"I" being the amperage (current)
"R" being resistance.

[TwoJ's]

Shitty solder job isn't unlikely. This was really the first thing I've ever soldered and i just did it, no one showed me or anything. I think it just needs to be done again with better care. I can also measure resistence of the circuit and see exactly what's going on.

Do you happen to know the amperage that something like this should operate at? I guess I need to check out the wiring diagrams.


Back on topic again, thanks for the write up. I'll look again for Demon Tuning.

[AndrewBird]

Interesting you say that about the solder Luke, I didn't know that. I'm a bit shitty at soldering, so there was a lot of solder on the connections when I built a harness for my heated seats. They don't get as warm as I would like, so the high resistance may be the culprit.

Looks like I need to pull the carpet again and re-do the harness.

That shouldn't be the problem. While a solder joint is a high resistance connection, it's not really enough to matter. If it was, computers wouldn't work correctly.

Now, if your solder joints were shitty and had porosity in them, then it MIGHT be your problem, but still, I seriously doubt it is the problem.

Anyways, enough OT.

[JamesE30]

And Jamese30, do you know the name of the seller you bought from? Can't find them on ebay.

I'm not sure i can remember they're exact name, but ill look it up for you.
I know it's from Demon Tuning though

[TwoJ's]

And Jamese30, do you know the name of the seller you bought from? Can't find them on ebay.

[TwoJ's]

Interesting you say that about the solder Luke, I didn't know that. I'm a bit shitty at soldering, so there was a lot of solder on the connections when I built a harness for my heated seats. They don't get as warm as I would like, so the high resistance may be the culprit.

Looks like I need to pull the carpet again and re-do the harness.

[AndrewBird]

Excellent diagram, I like the diode for the latching relay isolation, nice touch. BTW what did you use to make the drawing?

One thing that should be mentioned though in this diagram for people building this is there is no starter relay on these cars. Everything in your diagram would be fine though assuming that there is a proper current rating on the button, and the wiring and wire connection quality is up to par.

Only reason for mentioning is some may opt for that aftermarket "engine start" button, and I know that thing isn't rated for squat. It will work fine though with the addition of an actual starter relay.

AutoCAD was used to make the diagram.

As far as the starter relay thing, I mainly just put that to clean up the diagram a bit. I also have this in mind for my MG, which has a starter relay. Basically, if your car doesn't have one, you will need to wire in another relay for this circuit to control.

Also, assuming you use a starter relay (which is needed), there should be low current flow through the switch. All that would be needed is enough to turn the relay on.

To OP - That button looks really good in that hole. Almost looks factory.

[nefarious7907]

Looks nice, I havent seen very many RHD E30's.

[JamesE30]

Sorry guy's, finally uploaded some pictures in my original post.

I mounted it in the cigarette lighter hole, It's designed to be a perfect fit,
It requires a little fabricating to get it to fit and sit nicely, but I'm happy with it for now.

I intend to relocate the lighter to the glove box if i decide to keep the button...