Dead Headlight

Dennis Moore

XS400 Enthusiast
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Location
Columbus, Ohio
Friends. I have a dead headlight on my 1982 XS400RJ. All other lights work--turn signals, stop/taillight, instrument lights, plus the neutral, oil and blinker on the center cluster. I took apart the Low-Hi beam switch to see if there was any obvious problem. Everything looked good although you can't really can't see the rocker switch innards. Battery is strong. Only a year old. I took it up to have it load tested just to be sure. I went ahead and bought a new bulb since the one in there looks like the original. The new one doesn't light up. So, I checked all the connections and did a voltage test at the three prong connector. Negative volts. I checked the fuses. There are four fused lines under the seat. All fuses were good although I'm not sure what they specifically serve as they're not marked like in a fuse block. According to the electrical diagram one of them should be the headlight fuse unless there's another fuse for the headlight somewhere else. The only other thing I can think of is the ignition switch itself since that's what energizes the headlight. I've never taken one apart but I'm sure there are contacts in there that could be worn or dirty. It may not be serviceable. I don't know. Any words of wisdom?
GaugeCluster.jpg
 
Was the bike running? The headlight turns on when the bike runs. There is a relay for this also.
 
Stole the pic from Pete.........it looks like this but could be anywhere on your bike. Not sure what year that pic is from. It should have 4 prongs on it.

headlight-relay-jpg.31233
 
OK. I see it now. Thanks. I haven't seen anything like this but I'm still looking. It's funny that the electrical diagram for my model, 1982 xs400rj, doesn't show a headlight relay. There is a headlight fuse which is fine.
 
I disassembled the ignition switch and there was some grime on the contacts so I sanded it off. Put it back together and the headlight still won't come on.The spade fuse for the wire for the headlight is good. It may be that the contacts for the ignition switch are worn just enough to be the problem so I ordered a new ignition switch. I really don't know what else it could be. All connections are tight and there's no loose or worn wires that might cause a short. Barring finding a headlight relay I'm assuming it's a bad ignition switch.
 
Ah DOHC so may be different.......I thought SOHC bike. I have a DOHC 83 maxim but its in pieces......
 
I thought I hit pay dirt when I removed the tank and saw these two relays but one is the starter cutoff relay and the other is the side stand cutoff relay. I'll keep looking but I'm running out of places the headlight relay could be.
Relays.jpg
 
From the diagram and the list of components in the manual it does not appear that DOHC bikes have the typical relay.
 
From the diagram and the list of components in the manual it does not appear that DOHC bikes have the typical relay.
I sure can't find one by looking intensely with a flashlight and every angle possible. I've examined every connection closely to see if maybe a wire came loose or frayed. Nothing. Everything looks solid. I even replaced the 10 amp spade fuse for the headlight even though the one in there looked good. No luck. My hope is that either the ignition switch contact for the headlight is worn or the key turn mechanism isn't advancing far enough to reach the headlight contact. I have a brand new ignition switch on the way. Should be here tomorrow. Thanks, BBS360.
 
I installed the new ignition switch but still no voltage to the three pronged bulb connector. There is continuity in the hi and low beam wires to it from the hi-low beam rocker switch which I think is the problem. The contacts are probably dirty or worn but it's sealed and can't be serviced. The turn signal and horn switches are part of that left handlebar assembly and working fine but you can't buy the individual switches. You have to replace the entire assembly. I saw a NOS one on EBay for $60. I don't want a used one if I can avoid it. Hopefully that will solve the problem.
 
Talk about timing. The NOS left handlebar switch assembly was on Ebay UK and the seller does not post to the US. It just so happens that I'm leaving late this week to visit family in Scotland, a trip planned a year ago. So I'm having it delivered to my sisters house in Edinburg where we'll be staying for ten days. How lucky can you get There are plenty of used LH switch assemblies out there but a NOS one is a rare find. It's almost scary.
 
Well. The replacement LH switch did not solve the problem. I installed it yesterday and there's still no headlight. The horn and turn signals work fine. So the problem has to be somewhere downstream of the connector in the headlight bucket that the LH switch couples to. I'm still not absolutely sure there isn't a headlight relay somewhere. Spectra, it looks like the one in the pic you posted is buried down under a side cover or lower frame area. My bike is a DOHC Seca400 that has two relays underneath the tank (pic is above). One is for the side stand and the other is for the starter cutoff. Any ideas? Thanks.
 
The relay Spectra showed was from my 1980Xs400G. It may not be included in your DOHC bike. Have you applied power to the lamp itself? You may just need a new headlamp.
 
It's odd that the wiring diagram shows the Starter Circuit Cutoff Relay (#4) but dosesn't show the Sidestand Relay which is next to it under the tank. That makes me wonder if there isn't a Headlight Relay somewhere.
 
The relay Spectra showed was from my 1980Xs400G. It may not be included in your DOHC bike. Have you applied power to the lamp itself? You may just need a new headlamp.
Hi Pete. Yes. I tested the headlight directly off the battery. I bought a new bulb too since the original could fail any time. The spade fuse for the headlight is good. I put a new one in just in case. I bought a new ignition switch and the left handlebar switch is NOS that I just installed. I'm stumped. Thanks.
 
I can assume from this description from the manual that this DOHC model does not have a headlight relay. And this is exactly what the bike has done until recently.
Lighting Check.JPG
 
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