Dimmer switch malfunction?

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
dogred
Posts: 205
Joined: Sat May 16, 2009 10:15 pm
Car: 1983 D720

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My dashlight dimmer switch I think is malfunctioning. I turn on my headlights and I get only headlights, no dash or running lights. After the vehicle warms up to the second line on the gauge (this is a rough measurement) the dash and running lights kick on.

Is anyone else having this problem?

The only thing I can find that is common is that power touches some oil sensors that power the lights also.


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PEZi
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Car: Mitsubishi Lancer Evolution IX Mitsubishi Racing Edition
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never had that issue... and i suck at wiring stuff too so im glad

i personally don't have dash lights anymore tho

damn
Posts: 55
Joined: Tue Oct 06, 2009 7:13 pm
Car: 1986 Nissan 720 z24, Automatic trans

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dogred wrote:My dashlight dimmer switch I think is malfunctioning. I turn on my headlights and I get only headlights, no dash or running lights. After the vehicle warms up to the second line on the gauge (this is a rough measurement) the dash and running lights kick on.

Is anyone else having this problem?

The only thing I can find that is common is that power touches some oil sensors that power the lights also.
I think the dimmer switch only control's how bright you want the interior lights to be..Sounds like it could be a bad relay.

flinterman2000
Posts: 1011
Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

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Are you talking about the high/low beam switch. According to the service manual there is no dimmer switch. What happens in my truck, the high beams come on for themselves after you turn on the lights. A little play with the low beam and it comes off. The problem is the high/low beam switch.

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Project Trucker
Posts: 166
Joined: Tue Aug 18, 2009 11:50 am
Car: Datsun 720 pickup

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for my truck it takes a minute for the lights to come on then every thing is up and ready to go

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PEZi
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flinterman2000 wrote:Are you talking about the high/low beam switch. According to the service manual there is no dimmer switch.
there is a switch to the right of the steering wheel located on the dash that controls the brightness of the interior lights called a dimmer switch

Aven
Posts: 136
Joined: Wed Jan 20, 2010 6:42 pm
Car: 84 720 Kingcab
Location: South King County WA

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I was having issues with mine. I pulled the switch apart. The problem with mine was two of the three contacts from the rheostat had broken free. To fix it I soldered three small pieces of wire to the rheostat and then inserted them into the board and soldered them. Its not a great soldering job, but for my first, it worked.

dlarsona
Posts: 8
Joined: Mon Dec 21, 2009 9:46 am
Car: 1981 Datsun 720 and 1984 Nissan 720 king-cab 4x4's

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I had a similar problem but my headlights would also come on when the truck was just sitting - usually when it was raining outside. It got so bad that I had to park the truck away from the windows or disconnect the battery so it wouldn't wake me up all night: Lights on - lights off - lights on - lights off.

The switch was really easy to fix. I simply wrapped a piece of electrical tape around each contact "finger" so that it had a little more gap at the contact point. They're also easy to bend and could be adjusted that way as well I suppose...

dogred
Posts: 205
Joined: Sat May 16, 2009 10:15 pm
Car: 1983 D720

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Well I have just learned to use this as my guide to let the engine warm up first. It is just a small nusance right now. My truck has all the original wiring and plugs, no one has tapped, cut, sliced in to the stock harness.(which is a blessing) This problem had nothing to do with the dimmer switch, which I later found out by looking at the wiring diagrams. The switch works like it is supposed to.

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turbojunker
Posts: 40
Joined: Sat Dec 19, 2009 8:51 pm
Car: 79 510, 81 720, 72 510-RIP

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If you take the headlight switch apart and clean the contacts it will stop doing that. My truck used to do the same thing. Cold weather made it even worse. When it was below freezing it would take like 2 minutes before the parking and dash lights would come on.

dogred
Posts: 205
Joined: Sat May 16, 2009 10:15 pm
Car: 1983 D720

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Thanks for the info.


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