Instrument Light Dimmer

'92 Si VTEC · Post by **jjmartin349571** » Mon Jun 25, 2012 11:52 pm

Yeah, I learnt my lesson cocking about and briefly killing my radio, antenna, folding mirrors

lucky it was just a fuse!

Not had the car apart yet for fear of the ridiculous amount of stickiness and crumbling plastic that was going on last time

I'll take the tweeter cover off the drivers side and see if I can spy anything, if not the ball ache of removing clocks can wait for the weekend along with the other ball ache I have lined up - there's a H22A half stuck in the engine bay of my Accord

who's local??

Angus · Post by **Angus** » Wed Dec 26, 2012 5:04 pm

My BB4 had a dimmer switch in the centre console when I got it, but it never worked.

So I presume my car originally had a dim function, but on removing the dash smoked plastic, there was no dimmer control unit there. Also, I put EL dials in it a few years ago, so it's a different loom from the original.

Eventually, i got hold of a dimmer unit from a scrap car (it's a black box, held on by one screw onto the white plastic thing on the passenger side next to the fuel/temp cluster). I also got a USDM dimmer switch, which goes into the 3-button console to the right of the steering wheel.

What fun I'm having trying to get it to work. The USDM switch has 6 wires - 3 that go to the control unit, one to the fuel/temp gauge illumination wire and 2 for internal switch illumination (the front/rear fog switches I have in the console both have these illumination wires too. I notice from my garage junk collection that some fog switches don't.).

Previously, I had a simple switch in line with the dash illumination so that I could have it bright or dim with the lights on - cos the dim setting was far too dim if I had my lights on in daylight. I am bored with this, hence the current project.

There are 6 wires on the brightness switch ... 3 to the control unit, red/blk illumination in, red illumination out and an extra red/blk that goes to the fuel/temp gauges.

It looks to me that I don't actually have red wires coming out of e.g. the cig lighter where the circuit diagrams say they should be, rather there's a black. Indicating a simple earth.

My plan, once it gets light outside again, is to splice red/blk out of all the lighty-uppy bits (speedo, gauges, heater control, cig lighter) into a connection to the brightness control unit, and splice all the blacks out of the same places into a connection to the "red" on the control unit. The control unit then has its own "earth".

The only thing I can't quite figure is why the fuel/temp gauge has its own connection direct from the dimmer switch, though I suspect it may be that when the switch is rotated and clicked "off" it bypasses the dimmer control unit and gives full brightness all round.

If that works, I'll report back.

(The centre console version of the dimmer switch has only the 3 wires that go directly to the control unit, IIRC. i.e. it doesn't light up at all. So connecting it is easy enough - it's the control unit connections that are making my brain work!).

Angus · Post by **Angus** » Wed Dec 26, 2012 9:35 pm

Bugger. Going by the 1994 manual supplement with EL dials in, it looks like the dimmer control unit for EL dials is different from the little black box one for regular dials.

Think I'll try and connect my dimmer rotary switch as a simple switch in the meantime, i.e. off/on, bright/dim.

Back to the scrappy, to an EL dials car (I happen to know where there is one.

).

'92 Si VTEC · Post by **jjmartin349571** » Wed Dec 26, 2012 9:46 pm

Shame it didn't work, as this is something I really wanted to do to my BB4

I hate that just turning my sidelights on in the rain means I can no longer read my fuel/temp etc. I'd be interested in buying the control box off you though if you no longer need it - I already have a dimmer switch, so would it literally be a question of running wires from the control unit to the switch and dash?

Angus · Post by **Angus** » Fri Dec 28, 2012 12:11 pm

Well, the dimmer switch didn't work as a simple on-off (bright/dim) switch so I'm pretty much back to where I was.

i.e. I have an aftermarket little switch beside my gearstick that I wired into the red/black illumination circuit and means I can have the dimness on or off with lights on. Critical wire to splice into seems to be the red/black one from A4 on the temp/fuel array. I've connected my fag lighter and heater control red/blk wires to that one, then through the simple switch. Only disadvantage is I don't have any visual indication as to whether my lights are on now. No big deal.

You can easy have the black control box if you want - it's not going to work with my EL dials so no use to me. Just PM me your address and I'll send it to you.

There should be a connector on the loom that plugs straight into it, which presumably will connect everything up - I don't know, because I swapped the loom out of my BB4 when I put my EL dials in. Having said that, I may have the original loom in the garage somewhere, so will check later. Presumably, if you have the wiring under your centre console for the dimmer switch it should all just work with the control box in place.

The other possibility is that the control box will plug into the dash loom, but there won't be wiring for the switch. That's easy enough - there are 3 wires go from the box to the switch, so it'd just be a case of running 3 new wires down through the dash (either down under the tweeter, or there's a hole nearer the centre too) and along the centre tunnel to the switch.

If there's no connector from the dash loom to the control box it gets a bit more interesting - but shouldn't be too difficult. Just a bit time consuming. There's two red/blks from the control unit, and a red. Just got to connect them to the right places.