A different sort of turn signal problem

Hi Everyone,

Just picked up a 1985 maxim 750 last weekend some assembly required of course.

I am having an issue where I guess the guy who put the turn signals and headlight on thought electrical wiring was a simple task.

The turn signals don't work at all and before I go ripping the entire wire harness apart to start tracing I figured I'd turn to the Internet.

I have tested the lights by putting 12v to them and they all illuminate. The brake lights turn on without issue however the turn signals do not work.

If I push the turn signal switch left or right and I can hear the relay(41R-71) click and can feel it change position if I am holding and it proceed as above. The starter works and when I turn the key the relay also clicks so I don't believe it's the relay.

The wiring diagrams I've looked at all say the turn signal lights are on the dg and ch wires however none of those colours appear on the connections to the flasher and I can't find any reference to what wire goes to which terminal. I don't want to hack and slash or use hours of time doing continuity tests to figure this out if I don't have too. I was just wondering if anyone could help me out tracing this stuff by pointing me in the right direction any other quirks of these bikes I should know about since I am diving into the electrical on the bike?

 

Are they factory turn signals? Has the PO hacked the wiring a bunch, especially inside the headlight bucket?

 

They are not factory they are incandescent and yes there is a rats nest of bad connections in the headlight bucket.

 

Do both of the turn signals illuminate at this point and just stay that way? If so, then some things to check:

Verify battery voltage is 12.6 to 12.8V indicating full charge. Try hooking up a charger to see if they start working with the added voltage.
Verify 27W bulbs are installed, anything less there will not be enough current drawn to activate the flasher relay coil to open the contacts and start the flashing cycle.

The applicable wires to the flasher assembly (combination starter cutoff, flasher, and self cancel) are Br for power, Br/W for output, Y/R for reset to the self cancelling circuit, and W/G for the reed switch in the speedometer. The Ch (Left) and Dg (Right) wires appear at the output of the left control switch and should continue to the turn signals.

 

The lights do not come on at all unless I run a jumper from the battery. Haven't checked bulb wattage yet.

 

So I have continuity on the left control switch Br/w and the relay Br/w, dg on the switch to signals and the ch on the switch to signals.

 

OK so if I jump 12v from the battery (key off) to the Br/w wire in the relay harness and I active the turn signal switches the lights for whichever side is selected turn on and stay on until cancelled.

So looks like the relay may be the issue or the actual harness.

 

So the horn, tach, fuel sender, oil light all working? I know you said the brake light is working, is that a for sure or is it just the tail light. If the horn, brake, tach, oil light, fuel sender are not working, there is a fuse just for that.

 

The lights behind the gauges come on, brake lights come on when brake is applied. The Br/w never seems to receive voltage unless I jump it so could be a bad connection somewhere but seeing as I can jump it at the connector on the relay and it seems to make a good connection there I think it's a problem inside the relay.

 

It could be a defective module. On the older bikes with separate relays and when the turn signals do not illuminate it would be suggested to disconnect the self cancelling unit to see if they start working. Unfortunately, you do not have this option with the integrated assembly.

It looks like you have covered the bases quite well, the only thing I don't see is that you verified that the Br input wire to the module has 12V present.

 

Should have mentioned I was jumping Br to Br/w to verify that. Thanks for all the help guys.

 

Oh, and one other item is the reset, you have to make sure that is working as the module powers up with the flasher relay disabled. It will stay that way until reset by the Y/R wire being pulled low by a switch in the left control.

 

dg and ch wires are from the signals into the headlight bucket then they go to the control
in an 83 750 the signals connect to a 2 wire lead connector one is dark brown and the other is green,
do you have 3 wires coming from the signals? wiring diagram shows running light and turn signal
open up the control and see if the wires have come lose inside of it and clean it with electrical contact spray. lube with silicon spray or dielectric grease (bulb grease)

 

there is a brown wire going into the relay from the signal fuse

and a yellow/red wire and brown/white wire from relat to controler

and a blue wire from key switch to bulbs for running lights
#15 is relay unit #17 is handle bar control

 

Bought a new flasher at Canadian Tire and spliced it into the Br and Br/w wires from the original flasher relay all the lights illuminate and flash as they should. Thanks for all the info guys.

 

That will work but you give up the self cancelling feature. Did you check the reset (Y/R) before doing that?

 

Honestly the self cancelling feature isn't very important important to me but I did check for continuity on Y/r to the switch and w/green to the Reed switch and they check out but I couldn't get continuity or a measurable ohm reading across the Reed switch or any voltage so it may have been that switch causing the issue. I can dig into it deeper over the winter there is lots of cable management to do. Have to reattach the gas tank and petcock, replace spark plugs, get a new horn and reattach the headlamp.

 

The reset (Y/R) should apply a momentary ground to the Y/R wire when the turn signal switch is pushed either left or right to enable the flasher relay. If you hold the switch in that position, the ground should remain until the switch is released. If reset is not happening, the flasher relay will be held disabled by the self cancelling circuitry inside the integrated module. I don't have a pic of the 85 750 switch mechanism, but it is easily recognizable when opened as two small leafs that contact the slider mechanism when pushed left or right.

The best continuity test would be at the integrated module and placing one lead on the Y/R wire in respect to chassis ground. When the turn signal switch is pushed left or right there should be continuity to ground. If not, then it would be time to open the left control and evaluate.

Failure of the reed switch in the speedometer is more likely to disable the self cancelling feature, but the turn signals should still function. When checking continuity it will apply ground to the W/G wire and will be dependent on the location of the switch in respect to the magnet. If the front wheel is rotated you should see the switch opening and closing.