Separate glow plug dash light

[Jettage1]

Thinking about wiring up a separate dash light from the glow plug buss bar (92 Jetta Eco) so I know for sure when it's getting current.  I know some folks here have already done this mod, but I couldn't readily find any description.

The only question I have is regarding the amperage - I know that there are a lot of amps at the bar...  How do you wire it so that you aren't (a) melting your indicator wire, or (b) blowing the dash light?  I'm figuring there's something simple I'm just not thinking of at the moment. 

Thanks,

Steve

[burn_your_money]

As long as you don't wire it in in series you don't need to worry about the amperage

[Jettage1]

Not trying to be dense, but I'm not sure I see how I could wire it in series (unless I somehow daisy chained through the four plugs).

I was just going to put the positive terminal on one of the buss connections (like a ring terminal under one of the glow plug nuts) and the negative to ground somewhere under the dash.  It wouldn't tell me about each plug, only that the circuit was energized.

[Op-Ivy]

Not trying to be dense, but I'm not sure I see how I could wire it in series (unless I somehow daisy chained through the four plugs).

I was just going to put the positive terminal on one of the buss connections (like a ring terminal under one of the glow plug nuts) and the negative to ground somewhere under the dash.  It wouldn't tell me about each plug, only that the circuit was energized.

You could wire it in series by having the wire from the relay go to the light then the wire from the negative side of the light to the bus bar. The way you have planned to do it, one wire from the bar to the light is the way to do it!

[Jettage1]

Oh, duh.  That makes sense - I just never thought of doing it that way...

[Vincent Waldon]

What you're probably after is a light that tells you that power is making its way thru the relay, fuse, etc and actually getting to the glow plugs themselves.

If so, the best place to wire your light to is right on the buss bar itself (as you described initially)... and since the only power this new wire will carry is enough to run the light thin wire (16-18 ga) is more than enough:

- thin wire from light on dash to the glow plug buss bar.... spade lug that attaches to the glow plug itself is a good way to go

- other thin wire from light to a good ground in or around the dash somewhere

[92EcoDiesel Jetta]

quote: "You could wire it in series by having the wire from the relay go to the light then the wire from the negative side of the light to the bus bar. The way you have planned to do it, one wire from the bar to the light is the way to do it! "

If you do that the light will light but your glow pliugs won't get hot because the light is in series with the plugs,.

[burn_your_money]

I think the light would instantly burn out, and then no power to the GPs if you wire it in series.

If you look up by the fusepanel you might have a common ground connection that a female spade would slip over.

[Jettage1]

Yep, it would - it would essentially be acting as a teeny tiny fuse (very small filament) 

I'll find a ground somewhere - either a terminal or a convenient body screw of some variety...

[92EcoDiesel Jetta]

quote: "I think the light would instantly burn out, and then no power to the GPs if you wire it in series. "

I'll bet you $1 million that the light bulb will not burn out. Where's Vince Walden when you need him?

[92EcoDiesel Jetta]

I hope no one will take me up on the bet because you will lose! If the light bulb is a plain wire inside it will burn out like a fuse but a light bulb is not just plain wire but resistance wire (tungsten) and will limit the current flow to the glow plugs and will never get hot. Put the light in parallel with the glow plugs.

[Rabbit on Roids]

I think the light would instantly burn out, and then no power to the GPs if you wire it in series.

If you look up by the fusepanel you might have a common ground connection that a female spade would slip over.

how would the light instantly burn out? theres only the specified 12 volts going to it, just through a much more heavy duty relay. the glows would act as the ground to the light.

[vanbcguy]

Yup, you'd just have no glowplugs due to the resistance of the light...

For some reason this reminds me of the Mythbusters episode where they tested to see what would happen to a plane taking off on a giant strip of fabric being pulled the opposite direction at takeoff speed... It's all relative!! 

[Rabbit on Roids]

Yup, you'd just have no glowplugs due to the resistance of the light...

For some reason this reminds me of the Mythbusters episode where they tested to see what would happen to a plane taking off on a giant strip of fabric being pulled the opposite direction at takeoff speed... It's all relative!! 

exactly