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Sun Feb 28, 2010 7:32 pm

don't know. It is bolted to a heat sink that is bolted to the sides of the box. The box is bolted to the bus. We will let you know after we take it out on a night time drive. Could be a week or two. It dims the lights perfectly. I just wish I could have done a better construction job inside the box.

Sun Feb 28, 2010 7:39 pm

Just in case you missed it, see add'l comments on reply above. We both seem to be posting at the same time....

Sun Feb 28, 2010 7:45 pm

Quote: I just wish I could have done a better construction job inside the box.
No one says you can't rebuild it again. If you're like me, version 1 of anything is generally considered a trial / proof-of-concept pass...

Looks really nice on the outside...

Sun Feb 28, 2010 7:48 pm

Ok. When the parking lights are on the dash lights are on too. Then I will have to find a 12V circuit to tap into that gets its voltage from the parking lights because they can be on even though the headlights are off and the ignition is off. Might add a bosch relay circuit off the parking lights to limit interference. I don't want a short in this taking down the parking lights and some of the other lights. For now we won't use the parking lights seperately. Seldom do anyway.

Sun Feb 28, 2010 7:50 pm

Quote: version 1 of anything is generally considered a trial / proof-of-concept pass...

that is why it has a quick 4 pin connector on it and I bought two of everything :)

Sun Feb 28, 2010 7:58 pm

Quote: Ok. When the parking lights are on the dash lights are on too. Then I will have to find a 12V circuit to tap into that gets its voltage from the parking lights because they can be on even though the headlights are off and the ignition is off.
How 'bout headlight switch terminal 58 (the tail light circuit)? It has power any time 58b (the dash light circuit) does (hence the "b").

Just a thought...

Sun Feb 28, 2010 8:12 pm

The circuit has a 5 amp fuse designed into it on the 12V feed side. I haven't measured how much current it actually pulls at 14.5V which is about where the alternator runs. I don't want to overload any of the contacts in the switch or the circuits driven by them- that is the issue.

Sun Feb 28, 2010 8:49 pm

Understand.

The last time I opened a headlight switch, I recall the tail light contacts and slider being as husky as the headlight circuit, so the switch shouldn't (for a reasonable amount of add'l dash lights - say 5 amps or so) really care about the added load. And since the tail light fuses are after the switch, they won't care either, as you won't be going though them.

If you do want to use a relay, connect one end of the coil to H/L switch terminal 58; the other end of the coil to ground. Supply constant 12 volts (not from the switched side of the ignition switch) to relay contact 30; connect the output contact to the +12 input on the transistor booster circuit. Then, when the headlight switch is not off, the relay will be activated and supply boost power for the added gauge lights.

Side note: I modified my headlight relay wiring so that switching on high beams does not switch off low beams; thus all four filaments are on at once. Also running Cibie Z-beams with stock H4 bulbs. No relays added. After 25 years of operation, no ill effects to any lighting circuit component noted. Even the headlight bulb life seems normal (which is to say, I can't remember changing one in ages.) My conclusion is that the headlight switch can take it. Only weak spot seems to be that the cement holding the dimmer resistance coil in position dies of old age.

Now if you really want those added gauge lights off in parking lights only mode, you could instead drive a relay coil off of terminal 57 (parking light indicator) and use it to open the circuit between terminal 58b and the control input to the transistor booster, effectively killing the added lights when the headlights aren't on. You will need a small 12 volt coil normally closed relay to do this.
TD