Headlight/tail light/dash lights not working 82 XJ750 Maxim

Evening all. Update and progress on the 82 Maxim 750 project. Got it inside for the winter in my walk in basement and engine is running good. Thanks all for the help. Now onto the next issue I am having. Good ol electrical.

For the longest time the rear tail light did not work. Brake did, all lights did. I bought new bulbs and still no tail light. So I started diving into the wiring to find any breaks or what not. I bought new bulbs to replace in the cluster (by 80mph is burnt out) so I thought might as well check the headlight area. Well after doing that to no gain I now don't have headlight, aux light, or dash light(I never ended up changing the bulbs and it was just getting tedious).

So that's the issue. I now have no headlight, aux light, dash lights, or tail light. I can't find any fuses blown anywhere. Other than maybe a ground in the rats nest inside the headlight area, anyone have any suggestions?

Thanks in advance again.

 

The tail light and meter back lights are a separate contact on the ignition switch. The same contact is also used for the park position on the ignition switch where the tail and meter lights are illuminated in that "P" position. There is also an additional 5 amp fuse inside the headlight bucket on the Seca - not certain on the Maxim but likely located in there too. To check I would suggest finding and checking the 5 amp fuse and verify the condition of the fuse holder - it should be a blue wire and if the fuse is OK then use a DMM to verify if the ignition switch is supplying 12V to the fuse in the run or park position.

The Maxim uses a combination starter / headlight switch, which also includes the Aux light so both lights are active whenever the ignition switch is set to on. When you depress the starter switch the lighting contacts open to reduce the load on the battery It's pretty common for that set of normally closed contacts on the backside of the starter switch to need cleaning to restore headlight function.

And if you haven't checked the headlight fuse and fuse box condition or if the fuse box has not been updated it is a common failure for the clips to corrode and break causing no contact through the fuse.

 

Thanks for the reply.

Not sure what you mean by P position on ignition, I am assuming you mean on. I was able to figure out the blue and white wire leads from the atari in the cluster directly to the tail light. Moving it around made it come on. Wonder if somewhere in the wire is an issue.

I check that RH switch a few times and cleaned it and the contacts. It works properly to start, and the kill switch works properly also

. I checked voltage at the headlight, I am getting 4v when the key is on and 0v on the highbeam. When I switch to high beam is 0v on both connections.

Oddly enough my headlight has a "split" off connector for the low/high colored. Like it was powering something else or was direct connected somewhere. I can't find any loose open ended connections.

I am thinking I can just get a new set of switches and just replace them on the handlebars and bypass that headlight -turn off when starting - option on the RH switch.

Now I did discover when the previous owner added in, inline fuses the 30a and 10a BOTH when disconnected turn off the cluster. Not sure why they both would. I think some of the colors weren't matched properly. He did have to jump the solenoid to start it, I haven't had that issue.

 

CCW from off after the lock position - in the P or Park position the tail light and meter lights illuminate.

Not quite sure where you were moving wires but if you haven't cleaned and inspected connectors in the headlight bucket (recommended) perhaps the 9 pin connector that the L/W wire routes through has an intermittent connection? The tail circuit routes through the Atari and through a reed switch on the CMS to monitor tail light current and set a fault if less than expected current is detected.

If you think the switch is clean then time to get the DMM out and figure out where the voltage is dropping. Note the headlight also routes through the Atari to monitor current just like the taillight but the Aux light does not, so that would tend to point to the usual issue of the starter / headlight switch.

That is normal for the Maxim headlight connector - perhaps they were meant for a fairing hookup. They are not present with the Seca Atari.

The 30 amp is the main and should kill everything, the 10 amp signal will remove power from the Atari

 

So I made progress, think its solved for now, kinda.

Headlight was the black connector under the tank on the frame rail. The Blue w black stripe wire at the connector had voltage going in but not out. Removed that wire from both ends and directly connected and it fixed the headlight, dash lights, and aux light.

The tail light appears it was the 9 pin connector in the headlight bezel. The blue w white stripe wire wasnt staying connected at the connector. I did the same thing as the other connector and it seems to work but sometimes still cuts out if I bump the housing. I think its the wire and I might even re-run a new wire from there back to the bullet connector under the seat. Some the wires have wear of on them appears rubbing from the housing or heat from headlight(that thing is hot just testing it). I plan on getting shrink tubing connectors to make them better anyway, bunch are just taped.

Makes sense with the fuses, the wiring diagram is weird.

Thanks for the suggestions.

 

My suggestion for this, get to know the wiring diagram, get practiced with using the DMM to follow the supply voltage along the route (battery, fuse, switch, load) don't get sidetracked by the generator/rectifier/regulator, do your testing off the battery (ie bike not running). The Haynes manual which uses a coloured diagram is much easier to follow, so if you don't have this get to know the colour abbreviations used in your manual so you don't have to flip pages to read them (a separate key list does help here). Always, repeat always use voltage to check circuits, with the meter negative on frame earth, (having made certain the battery is well connected to the frame).
If you learn this skill once, it will serve you well, cut down your fault finding time, reduce cost of wasted replacement parts etc