I've just installed a Defi link controlled boost guage and the guage lights are dimming reverse from the interior lights.

The scuderiaciriani site says:

"I wired the gauge light in parallel with the ash tray light. e.g.- each wire on the gauge goes to a different wire on the ash tray. If you had tried to wire it to only one of the ash tray wires, this would result in a serial connection. People have reported that this causes the light to brighten when the dash lights are dimmed. Credits to Martin Crane and David Beale for pointing out that this is not immediately obvious."

I only have ONE wire leading from the controller for illumination - so I'm not sure how to apply the instructions above. I'm sure this should be obvious, but I'm a little confused. Any help would be appreciated.

Thanks

 

Sounds like the power is being inverted somewhere. Which wire do you have it spliced into?

 

Just for simplicity, I have my gauges spliced into the red (power) side of the ashtray light. It doesn't matter what you use for ground. It should be that simple.

 

You may need to attach a wire to the case of the gauge. If there is only one wire coming off the gauge, then the case has to be the ground.

 

The controller has:
1 red lead = constant 12V (for memory)
1 black lead = ground
1 orange lead = ignition 12V (for normal power)
1 white lead = dimmer controlled 12V (for illumination)

The illumination wire can lead to either side of the ashtray light as BOTH are a source of positive power.

 

Let me know when you figure it out. My old Apex'i peak hold boost guage worked just fine powered off the cig lighter light. My new PFS boost gauge works fine too, my SPI temp guage wired to the same wires is either full bright (wired this way) or opposite of all the other dash lights including the boost guage.

Jeff

 

1 white lead = dimmer controlled 12V (for illumination) ======> +12 volt side of your ashtray light

1 black lead = ground ======> A good ground source or the ground side of the ashtray light


This would put your illumination in parallel to the ashtray light. Everything else would go to their appropriate place. You could use the +12 Battery and +12 Ignition off of your radio if you wish or just run a temporary 12 volt wire from your battery to the guage if you don't want to cut into the harness prematurely.

 

I have a question but I don't think it relates directly to this one. I have a boost and water temp gauge in a pod and they are always too dim for me too see them at night even when I turn the lights on full bright. When I dim all of the lights the gauges also dim. These were there when I got the car so I don't know how they are wired. Basically is there a way to get my gauges brighter so I can use them at night without having to take my eyes off the road and concentrate on them. Is there another way to hook them up or do I just need better bulbs in them?

a solution to this would = me being very happy

 

I have the same problem with the Defi gauges. I spliced my white wires into the illumination line coming off the radio. It worked in opposite direction just like you are describing. I'll try the ashtray light next.

 

The best I could do is make the guage light turn on full force with the other lights. In this case, the guage light does not dim with the other interior lights, but I never dim my lights anyway.

To do this:

Keep your ground hooked up to a good ground bolt.

Hook the white guage wire (illumination wire) to the POSITIVE wire feeding to the ashtray light. This one reads like 10.5V when the lights are on. I was wrong thinking that either wire leading to the ashtray light would work.

Still, if anyone knows how to get the guage lights to dim as they should, please post it here for everyone's benefit.

 

As a side note:
With the following configuration the lights would dim as they should - with the ignition OFF. With the ignition ON, the guage would freak out.

White wire -> Pos ashtray wire
Black (ground) wire -> Neg ashtray wire

 

Same thing I ended up with. Guage light full bright.

Jeff

 

For gauges that have only one illumination connection, use the following. Don't ask me how it works, it came from a friend that had to hook up his gauges with only connector. I thought that I was going to have to do this, but my gauges had 2 illumination connections. I think most new gauges have 2 connections. It might be easier to get a new gauge.

Good luck, Adam


Rx-7 dimmers work like this:
>> >> >> >>
>> >> >> >> Switched +12V Illumination
>> >> >> >> |
>> >> >> >> |
>> >> >> >> |
>> >> >> >> Bulb
>> >> >> >> |
>> >> >> >> |
>> >> >> >> |
>> >> >> >> PWM Dimmer signal
>> >> >> >>
>> >> >> >> In this system, when the dimmer signal is pulled to ground (0
>> >Volts),
>> >> >> >> a current flows through the bulb. When the dimmer signal is
>pulled
>> >> >> >> to +12 Volts, there is no voltage difference across the bulb, so
>no
>> >> >> >> current flows and the bulb dims.
>> >> >> >>
>> >> >> >> However, these gauges, like most other electrical gauges, tie one
>> >> >> >> side of the backlight bulb to ground (0 Volts), which does not
>work
>> >> >> >> with our dimmer. Most cars work the opposite of ours, where the
>> >> >> >> dimmer signal is pulled to +12 to light the gauge bulbs.
>> >> >> >>
>> >> >> >> So what you need is a simple circuit to invert the stock dimmer
>> >> >> >> signal to what the gauge bulb needs to see. This is done with a
>> >> >> >> resistor and PNP transistor:
>> >> >> >>
>> >> >> >> +12V Illumination
>> >> >> >> |
>> >> >> >> |
>> >> >> >> /
>> >> >> >> 2K Ohm |L
>> >> >> >> dimmer signal -----VVVVV----|
>> >> >> >> |\
>> >> >> >> \
>> >> >> >> |
>> >> >> >> |
>> >> >> >> To the gauge bulb
>> >> >> >>
>> >> >> >> Almost any general purpose PNP transistor will do, since it will
>be
>> >> >> >> operating in saturation, not dissipating any power. Both signals
>> >> >> >> can be tapped from any of the dash illumination bulbs - I use the
>> >> >> >> cigarette lighter bulb.

 

Thanks for that info. I'm pretty good with diagrams, but I'm not an EE. What's all the \ | / ? The transistor has 3 leads coming out. Can you show how it's hooked up inline with the resistor? Thanks.

 

As I said before, I don't know how it works. Try this link, I hope it helps.

http://www.scuderiaciriani.com/rx7/e...iring.html#DIM

Adam