Headlight/high beam out on 85 FJ

[FJFAST]

Is it normal to get 8v out of harness before the EB harness.the relays wont fire.

[FJFAST]

When EB hooked up..power stops

[ct7088]

When the voltage drops under a load there is a connection that has high resistance. Check the same connections as before but do it with the relays connected. Check voltage at the output of the hi beam switch if < 12 volts check the input side if < 12 volts move to the stop/run switch. You need to find the the point of failure. Check both sides of the headlamp fuse with it still in the circuit and the headlight on. If there is still 8 volts at the headlamp fuse the next point of concern is the key switch. I used a single 40 amp relay to route 12 volts around the ignition switch on my 85, it dropped to 10.5 volts across the switch. That gave me full voltage at the headlight and the coils. Dropped the alternator charging voltage to 14 volts. I had already replaced the alternator connector as it was getting hot and was partially melted. I used a relay similar to this.

http://www.mouser.com/ProductDetail/Panasonic-Industrial-Devices/CB1-12V/?qs=sGAEpiMZZMt98bArVJter151%252bemUZjTwfnli5RpAUtk%3d

Chris

[FJFAST]

Chris..things seem to check out on both sides. I hooked up a new socket to original wiring..I get 8-10V out of both socket slots...but when I plug in bulb-nothing. Yes bulbs are good..

All ideas welcome at this point.  I am at a loss. My wife says just put the dang thing back together and we'll just ride in daylight..ha-ha.

[FJFAST]

Checked socket ground also,
it's good.

[FJFAST]

For those who have installed an Eastern Beaver kit..the instructions say to tape off original black ground wire from the headlight harness. Is this correct? If not, what do I do with it?

[ct7088]

The 8-10 volts that you read is it at the EB connector that plugs into the headlamp or the wires that come from the high beam switch? The connection of the red and black wires to the battery must be clean and secure. The ground from the original headlamp harness is not used, it would be best to insulate the end and tyrap it to the harness.

Chris

[FJFAST]

Get power from both the switch and the EB harness. The problem is when I connect them, the juice goes away.

[ct7088]

The low voltage at the original headlamp connector has to lead back the connections that you have already checked. Start with the headlamp fuse on the left side fuse panel(at least on a 85) The body of the fuse has an indention on both sides of the top check and compare the voltage at both points with the headlamp plugged in and turned on. I expect them to be within one tenth of a volt. Using the same ground point for the meter measure voltage to the positive battery post. Are the three measurements close to the same? The path for the 12 volts is from battery to ignition switch to headlamp fuse to start switch to the high beam switch and last to the head lamp socket. Either at or between these points there is a high resistance which will carry the small amount of current to make the volt meter work but not allow the much higher current of the headlamp to pass through. This could be the stranded conductor being broken inside the insulation but when you are investing your time the more likely suspect is one of the switches or fuse socket.  The start switch and high beam switch contact surface must be clear of corrosion but each also has a spring that pushes the contacts together. Pushing against the spring tension can break the contact loose. The list of possibilities isn't long. Establish the last place that has full voltage and that will identify where to look for the problem. My Dad taught me to split things in half and then into small parts until you find the problem. Divide and conquer. I'm no rocket scientist and I can do it and have taught a few others. When my kids learned to read it looked so hard and they said "I can't do this", until it all made sense. Yes you can.

Chris

[jscgdunn]

Sorry to see you are having so much trouble with this.  Might be good to send some pics of how you have the EB relay system hooked up.  The relays should take very little voltage to fire.  Basically the EB red goes to the + battery terminal and the black to the -.  I suspect your spliced connections may be incorrect?

Jeff

[FJFAST]

The low voltage at the original headlamp connector has to lead back the connections that you have already checked. Start with the headlamp fuse on the left side fuse panel(at least on a 85) The body of the fuse has an indention on both sides of the top check and compare the voltage at both points with the headlamp plugged in and turned on. I expect them to be within one tenth of a volt. Using the same ground point for the meter measure voltage to the positive battery post. Are the three measurements close to the same? The path for the 12 volts is from battery to ignition switch to headlamp fuse to start switch to the high beam switch and last to the head lamp socket. Either at or between these points there is a high resistance which will carry the small amount of current to make the volt meter work but not allow the much higher current of the headlamp to pass through. This could be the stranded conductor being broken inside the insulation but when you are investing your time the more likely suspect is one of the switches or fuse socket.  The start switch and high beam switch contact surface must be clear of corrosion but each also has a spring that pushes the contacts together. Pushing against the spring tension can break the contact loose. The list of possibilities isn't long. Establish the last place that has full voltage and that will identify where to look for the problem. My Dad taught me to split things in half and then into small parts until you find the problem. Divide and conquer. I'm no rocket scientist and I can do it and have taught a few others. When my kids learned to read it looked so hard and they said "I can't do this", until it all made sense. Yes you can.

Chris

The low voltage at the original headlamp connector has to lead back the connections that you have already checked. Start with the headlamp fuse on the left side fuse panel(at least on a 85) The body of the fuse has an indention on both sides of the top check and compare the voltage at both points with the headlamp plugged in and turned on. I expect them to be within one tenth of a volt. Using the same ground point for the meter measure voltage to the positive battery post. Are the three measurements close to the same?

The voltage checks out on all three points from a ground point and also off th battery ground.

[FJFAST]

The 8-10 volts that you read is it at the EB connector that plugs into the headlamp or the wires that come from the high beam switch? The connection of the red and black wires to the battery must be clean and secure. The ground from the original headlamp harness is not used, it would be best to insulate the end and tyrap it to the harness.

Chris

8-10v both fron EB and wires from high/low switch.

[FJFAST]

Sorry to see you are having so much trouble with this.  Might be good to send some pics of how you have the EB relay system hooked up.  The relays should take very little voltage to fire.  Basically the EB red goes to the + battery terminal and the black to the -.  I suspect your spliced connections may be incorrect?

Jeff

The EB relay setup correctly as far as I can tell. Right now it's disconnected. I just want the lamp to work on OEM wiring and I'll go from there.

[ct7088]

measure voltage from the low beam wire to the battery positive post - that will show the voltage drop across that circuit. The lower the voltage reading the resistance between the two points. Key on with the light switch in low beam position. Measure voltage across the two battery post ? 12 volts? Measure voltage from the positive post to a good ground on the frame of the bike, somewhere away from the negative battery cable. That should be within  a few tenths of a volt of the measurement across the battery post. It is beginning to sound like the negative battery cable is bad or the contact point to the frame maybe the connection of high resistance. Did you measure the battery voltage using the same ground that you used measuring the two light sockets? The electrons leaving the battery must have a path back to the other post. I'm told that the direction of electron travel is out of the negative post through the circuit and back to the positive post. What matters isn't the direction but the path must be complete before the electrons can do their job.

Chris

[FJFAST]

Ok all....looks like I finally have this thing licked. Took quite a while but there was a bad negative ground coming from an old radar detector module. When I disconnected the negative wire, the lamp lighted. Unbelievable. I will say I learned a lot about this stuff as frustrating as it was. I would like to give a heartfelt thanks to everyone who chimed in with trouble shooting ideas. I hope to get the fairing back on this weekend (fingers crossed on that one) and will give you an update.

Greg