What have you done to your car today?

[marcs_sp20]

Ah ok coolies, just staying the stock colour??

I just went & put air in the tyres, well it does constitute doing something to the car

[Orion]

Changed all the insturment cluster bulbs
Started rewiring the gauges
Took it out on the southies to 'test' various suspension setups
Will give the interior a vacuum a bit later

[Aaron]

Originally Posted by marcs_sp20

Ah ok coolies, just staying the stock colour??

I just went & put air in the tyres, well it does constitute doing something to the car

Undecided, it's got a "stock colour" engine bay so that's a big incentive to stay stock, or close to stock (plus I like the colour). But that's a lot more stripping away.

A.

[Dogo]

I've finished the airbox / intake pipes and the gearbox is about 1cm from being back on ( thanks Dan ). It just needs that last little wiggle / shove and it can be bolted up.


We came across something odd with Dan's dash lights. The dimmer switch doesnt seem to be working. We came to this conclusion because if you bypass the switch, the dash lights up as usual. The odd thing is that we tried it with my switch, and Dan has tested with others - none work !
I'm sure mine is ok, so we're left confused.

The dimmer is a strange setup - according to the diagram is has some kind of oscillator inside it. I wondered if it needs the constant 12v rail to work , but this was reading as active too.

[Rupewrecht]

Originally Posted by Dogo

We came across something odd with Dan's dash lights. The dimmer switch doesnt seem to be working. We came to this conclusion because if you bypass the switch, the dash lights up as usual. The odd thing is that we tried it with my switch, and Dan has tested with others - none work !
I'm sure mine is ok, so we're left confused.

The dimmer is a strange setup - according to the diagram is has some kind of oscillator inside it. I wondered if it needs the constant 12v rail to work , but this was reading as active too.

Is very weird.

Now i have to put my dash back together. Gah!

[70NYD]

so it was the switch?? im confused now cus u tried other ones.. is it working all good now?

[Aaron]

Yeah, the dimmers are not resistive, instead they give 12v and vary the frequency so the light is basically flickering on/off really fast and the human eye perceives it as dimmer. Makes the system work with LEDs and stuff (how late model falcons etc do it).

The trick for modders is that the wiring shows 12v with a digital meter, but will show a varied voltage with an analogue meter (as the analogue meter works much like a lightbulb).

I'd say the switch thingo is fried

A.

[Rupewrecht]

But we tried 4 different switches!

[70NYD]

hang on if dogo said its battery bulb switch ground is there a chance that the grounding point worked loose... or something.. cus if you tried four diff ones its not the switch, and if there is voltage to the switch, and the switch works, then there has to be a break after the switch that is stoping it from working... right?

[Dogo]

The switch is a negative trigger. The only thing after it is the ground , and that passed when I tested it for continuity to the chassis.

Referring to attached diagram,
R and R/B tested 12v with the headlights switched on. R/Y ( the audio wire ) I think was dead, but that would be because Dan has an aftermarket head unit. The black wire passed the continuity test to ground.

With the bypass in place, the dash lights up, but there's no dimming control ( obviously )

I can't see how both our switches wouldn't be working but once the battery is back in I'll test mine

[Dogo]

Oh and my news is that the gearbox is back in, and I've bought some B6T rods for when I rebuild my engine. Thats the next big fun project.

[Aaron]

Have you disconnected the Audio unit lead? It may be possible that it's somehow disabling the dimmer function

[70NYD]

most aftermarket headunits dont have a dimmer function, so you will never connect it to the switch anyway.. thats so strange dan, this is why i hate electronics >

[DavoAust]

i had this problem when i pulled the dash apart to put the new HU in. no idea what it was but i pulled it all apart and put it back together again and it worked

EDIT: wait i think it may have been to do with the current through the switch, and the plug may not have been in right. checked you have good current through the switch? ie. plug isn't stuffed

[Aaron]

My theory is most headunits use a 12v to trigger their "Dim" mode if they have one, but in this case the trigger line may not impose the correct load (due to trigger input impedance or the wire itself is shorted/damaged) and therefore disabling the dimmer function.

It's a car, it has tyres therefore it's trouble

Incidently the External Amps in the MX5 have stopped working, but the power antenna control (which also triggers the Amps) still works fine. Both amp fuses are fine..... Bloody magic gremlins

A.


A.

[shaikaka]

I had a can of paint and some time....

[Dogo]

Ow you're blinding me !

Hehe actually it looks alright. My bro's skyline has a white dash too

[Dogo]

Originally Posted by Aaron

My theory is most headunits use a 12v to trigger their "Dim" mode if they have one, but in this case the trigger line may not impose the correct load (due to trigger input impedance or the wire itself is shorted/damaged) and therefore disabling the dimmer function.

I suspect the audio line is the culprit too. But Dan hadn't changed anything to do with that when it went from working to not working.

Aftermarket head units dont use the negative wire of the audio light. Thats why the R/Y wire would be dead. But if its shorted against something that may stop the oscillator from working.


I dont suppose it matters until Dan cares that his dash is full brightness. He tells me he keeps it on the highest setting anyway.

[70NYD]

Originally Posted by Aaron

My theory is most headunits use a 12v to trigger their "Dim" mode if they have one, but in this case the trigger line may not impose the correct load (due to trigger input impedance or the wire itself is shorted/damaged) and therefore disabling the dimmer function.

It's a car, it has tyres therefore it's trouble

Incidently the External Amps in the MX5 have stopped working, but the power antenna control (which also triggers the Amps) still works fine. Both amp fuses are fine..... Bloody magic gremlins

A.


A.

i dont have the dimmer function for the DVD and the dash works fine, so i cant comment there but as for your MX5 trouble i can tell you i had same problem with my old HU
what happend was that i accidentaly earthed out the trip wire cus of a faulty lightup switch (i have a switch that turns amps on off, cus sometimes im sick of bass) and it fried part of the internal circuit. now the thing was there was enough current sent thru the wire to trigger the anten by itself but not amp.. lucky it was on my old crappy HU, so now with this one (and a new crappy switch haha) it works fine. that might be the problem, if you have a multymeter check how much voltage/current your getting at the amp trip terminal..
i hope that helps
Tony

[Rupewrecht]

The only change to that wiring has been the addition of a second bulb in my boost gauge to make it brighter (wired in parallel just before the gauge) which is tapped from the cig lighter wiring. Nothing else has changed!

And that thing that confuses me is that it worked fine for 2 weeks like that.