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Headlight switch/Combination Switch cleaning/repair


spddm0n

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My headlights started having a problem recently, in which one of the high beam light bulbs wouldn't turn on, and then would randomly come on as I was flipping the settings on the combination switch (the stalk on steering column) between high beam, low beam, and flashing high beams.  I determined the problem being in the combination switch.

 

I went to the salvage yard yesterday and picked up a replacement (an '84 720 randomly showed up there recently, and rarely are these available near me).  I was so excited to find one that looked like it had recently been replaced on the truck in salvage, just before it ended up in the yard.  I went to pickup other parts, but when I saw the good-condition combination switch, I grabbed it.  Turns out, it's different than mine.  Looks like Nissan changed the part just for 1985.

 

In early models, there are three connectors built into the back of the combination switch.  On the late models, there are two, with one pigtail of wires hanging off the combination switch with the third connector on it (which is a different pin shape).

 

I'm likely to try and clean/repair the combination switch I have.  Has anybody ever done this or have any advice for me?

 

Thanks!!

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The light switch turns both on so if one beam is on the other should be also, so this precludes the switch or the hi/low relay being the cause.  Swap the high beam bulbs and see if the problem moves. (bad bulb) Might be just a bad plug in connection at the bulbs and moving them may clear this up.

 

Nissan headlamps send power to all bulbs when the headlight switch is turned on. What the hi/low switch does is trigger a relay that selects which bulbs are grounded to turn them on. 

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Hmmm...I went though all the bulb swapping etc. yesterday. The problem remains on the same side. The only thing that reproduced the behavior was flipping the stalk in the combination switch. I couldn’t find the wiring diagram in the FSM either, so I couldn’t verify how it was working. 

 

I imagined the head lights (together) would get the same signal from the combination switch, but I noticed the behavior being different. Perhaps something funky with the relay, depending on electrical load or something. I have another relay I can swap it with.   I’ll try that.  

Edited by spddm0n
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Well, I dug into the combination switch a bit more.  There is definitely something wrong with the combination switch somewhere in it.  When I turn the lights on, then push forward on the stalk, only the driver-side bright bulb comes on.  Then, if I gently "tap" on the plastic body of the combination switch, the passenger-side bulb will light up.  I can't isolate where the problem is in the switch, but it certainly does appear each headlight is getting a separate signal from the switch.  I still can't find a wiring diagram for the system though.  Even in the FSM.  It's not showing the head lights in the "lighting" area of the EL section.

 

I may try to remove the stalk from the new switch and swap it into the old switch.

Edited by spddm0n
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I only have the '84 FSM so perhaps the '85 is different. Many have had trouble with the lighting switch which tends to be the grease used on the switch contacts and... age + dust. A good spray with electrical contact cleaner/lube often flushes it out.

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2 hours ago, datzenmike said:

I only have the '84 FSM so perhaps the '85 is different. Many have had trouble with the lighting switch which tends to be the grease used on the switch contacts and... age + dust. A good spray with electrical contact cleaner/lube often flushes it out.

The truck I found in salvage is an '84.  It was a 2WD version that did not have intermittent wipers (mine does), and the body of the entire unit had a different layout, so the clam shell plastic that surrounds the steering column won't align correctly.

 

It did look like a good cleaning might work, but it could also use a bit of sandpaper on the contacts.  I actually was able to remove the entire electrical contact assembly in the new unit and swap it into my old unit, refreshing just the headlight switch part of the unit, so it all worked out.

 

By the way, the combination switch does activate individual (LH, RH) headlights individually.  It does, however, operate the low and high beam on the same side on the same circuit of the headlight switch part of the combination switch.

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The headlight switch is completely seperate from the wiper switch so what is the problem.  If the plug for the 84 headlight switch is the sam e as the 85, take the headlight switch out of the 84 combination switch and install it in the 85 combination switch if these are the same.  Some times you have to crawl out of the box to think!  LOL

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9 hours ago, Charlie69 said:

The headlight switch is completely seperate from the wiper switch so what is the problem.  If the plug for the 84 headlight switch is the sam e as the 85, take the headlight switch out of the 84 combination switch and install it in the 85 combination switch if these are the same.  Some times you have to crawl out of the box to think!  LOL

These headlight "switches" are all combined in the combination switches with the wipers.  I did end up using part of the headlight switch (the little box of electrical contacts) from the new combination switch, and swapped it over to the old one to replace the contacts that weren't working.  I didn't swap the stalk itself, as it seemed to not want to be removed.  I was in a bit of a hurry too, so I might revisit that at some point (the only reason I would do this though, is because all the white lettering on the old stalk is wearing out and the new one looks pretty). 🙂 

 

Yeah, effectively, I did swap the headlight switch from one to the other. 🙂

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By the way, I finally found the page with the electrical diagrams for the headlights.  Who would have thought they would be with the combination switch??!!  🙂

 

meQg1FMh.jpg

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I still can't see how one high is on with the other off. The relay grounds Red (hi beams) OR Red/Yellow (low beams). It doesn't ground them separately. This looks the same as my '84 manual.

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