1985 Big Red No Power to Ignition Switch

[Aaronw9]

My 1985 Big Red doesn't appear to be getting power from the battery to the ignition switch. The battery has 12.6V in it when I test the battery side of the Starter Solenoid I have the same. But I tested the red wire soldered to the back of the switch and there was only 9 volts. It acts just like it don't have a battery init. It wont crank, no neutral light(yes it is in neutral), and no lights. The main fuse isn't blown. I took the battery out and put in my other 85 Big Red and it started no problem. What could be the issue here? Thanks in Advance.

[deejaycee_2000]

Replacing the ignition switch will be a good starting point, if that doesn't solve your problem you will have to start one point and check the whole harness for breaks or bad connection points.

[Aaronw9]

Is there a plug on the back of the switch that all the wires go into or are some soldered to it? To me it looked like some wires were soldered to the switch.

[ps2fixer]

The ignition switch unplugs from the harness, I don't think Honda makes any component permanently attached to the main harness except internal resisters and diodes.

The red wire at the ignition switch is battery power source, so 9V there has nothing to do with the ignition switch being good or bad so don't blindly replace parts. 9v vs 12.6v indicates there's a high resistance spot between the battery and were you measured, so could be a broken wire just barely touching together, corroded wire, corroded connectors, or poor switch contacts, or something similar. The only exception is if you read battery voltage, then turned the key on and tested the wires, you changed something and a high draw could bring the voltage down, but it would show up at the battery too.

Here's a place to get the service manual for the 250es, this pdf of the manual kind of sucks because there's no book marks. Most of the instructions for tests etc from the 250sx manual can be used, but the 250es manual you'll want for the wire diagram. It's on page 273 and 274.

http://www.oscarmayer.net/atc/manuals/

Anyway, low voltage at that location there's not a whole lot that can be wrong. The first thing I'd check is the fuse under the seat (20amp glass type). It comes off the positive battery cable at the starter solenoid. It runs though a bullet connector to connect into the harness, then runs to the voltage regulator and ignition switch, so internally there's a 3 wire splice factory. The last spot I can think of for a poor connection would of course be at the battery, but you got battery voltage at the solenoid so that should rule that out, and also the ground wire to frame.

Even at 9v at the ignition switch, you should still get dim lights. What's the voltage reading with the ignition switch on and testing the black wire (the power output wire)? The black wire runs to the regulator and the fuses behind the headlight under the black cover to power the aux plug and the rest of the harness (lighting side of things). It comes out as black/brown. The neutral/reverse lights connect to that black/brown wire (and the handle bar controls power source wire). If you have power to there then the ground side of things for the neutral/reverse lights might be the issue, or blown bulbs.

The neutral/reverse bulbs ground though the neutral and reverse safety switches which connect to engine ground when in the related gear. The sub harness for them fails fairly often from oil exposure and such. Make sure the sub harness is plugged in at the bottom right side of the engine under the metal cover. You can also test the switches while you are there since you have a multi meter. Set it to ohms and read the ohms though the switch contact pin and engine ground. Neutral only should have connection while in neutral, and the same for reverse. The CDI *MUST* have signal that it's in neutral or it will not fire the spark plug even when kick starting (guessing the machine is non-running besides the battery power issue).

FYI, the battery/lights have zero effect on the ignition system. Critical parts for the ignition system are the exciter coil, pulse generator (also called a pickup coil for those that work with cars), CDI box, the kill switch wire (goes to kill swtich & ignition switch, disconnecting and leaving the black/white wire unplugged will give spark normally), ignition coil, harness/coil frame ground (so spark plug has a ground connection to the coil), and of course the neutral safety switch so the CDI will allow the machine to be started.

Good luck with the diag work, and let us know what you can find. Best to diag the issue out instead of throwing random parts at it, unless you have money to burn and just like new parts on your machine for no reason. FYI, the ignition switch is in production yet, so if needed you can get a new one from Honda. I can give how to test it if you want.

[Aaronw9]

The fuse I checked was a 20 Amp by the battery but wasn't a glass type it was a modern automotive style it wasn't blow. The machine does run fine if you kick start it it's just not getting power from the battery, also I think I forgot to mention the neutral light does come on when cranking with the kick starter but is just running off the stater. I will have to test for power at the output wire, I assume I wont have to test for current at the neutral/reverse switch since it starts with the kickstarter?
Thanks for the help.

[ps2fixer]

Yea if the neutral light comes on when you kick start it, then we know the neutral safety circuit is working (the switch atleast). Reverse is a bit of a null point since it's just the light on that machine.

Sounds like you need to track down where you do and don't have battery power. With the switch on, test at battery to get your base line voltage. Compare your results with each step of the way though the harness and you should be able to spot where the voltage drop happens and help to focus where the problem is. A small voltage drop is normal, but not a lot, like 0.1v isn't a real big deal, but 3v is.

Here's a list of things to check in order from the battery. Sounds like the fuse was replaced, the OEM style is a glass style in a white plastic clam shell housing, then that sits in a rubber housing (photo at bottom of post). Not really a big deal if the splice work is solid. If you can tug on the area that it was worked on and it comes apart, it needs to be redone. B Crimp is best, but not many have the special tools for that, next best is a U crimp with the proper crimper. 3M makes butt connectors with adhesive heat shrink to seal the connection, your local automotive parts store should carry them. Soldering is always an option, but remember solder isn't perfect, it's not exactly a strong metal and over time the connection can fail and still needs to be sealed.

Anyway, here's the list of connections to try to isolate where the battery drops from 12.6v to around 9v. All readings should be done with the negative probe on the negative battery terminal for the best ground possible.

Fuse connector on battery/supply side
Other side of fuse to be sure the fuse isn't the cause (since it's an automotive style, these two readings should be possible to get at the top side of the fuse where the metal is accessible for testing).
Voltage regulator Red wire (at the connector, harness side)
Ignition switch Red wire (at the connector, harness side)

This one's a little more tricky, the black wire from the ignition switch, you have to have the switch plugged in and turned on still and "back probe" the connector. Basicaly run the probe in where the black wire goes into the housing and it should get a connection.

Let us know what the results are like and I'll brainstorm what it might be, or atleast which section of wiring to inspect closely.

Also, if you don't care about it being more of a hack job type of repair, you could cut the wire after the fuse and splice in an extra 14 guage wire, and tie it in at the ignition switch red wire. It's kind of a hack job fix, but it generally works for wiring issues.

[Quintin]

If it started with the battery from your other Big Red so I would suspect the battery. Check the battery voltage when trying to start it. Sounds like a bad battery that has a surface charge. I see that alot. Voltage but no amperage. Consider electricity as a fluid. With flow "voltage" it will fall out of a hose but without pressure "amperage" it won't accomplish anything.

[Aaronw9]

Quintin, No I took the battery out of the one I'm having issues with and it started my other bigred.

[shortline10]

On that machine it’s usually the fuse connections or the ignition switch , very common problem on that model . The switch can be taken apart and cleaned up .

[ps2fixer]

Generally electricity is viewed as water in the respects of a stream, depth is voltage, current/flow speed is amperage. It makes more sense that way when you get into diodes and such (0.7v min to even get past it). The water idea never worked for me too much though, just learning the characteristics of different parts and follow the paths they can take is how I learned so far.

Also he got a 12.6v reading at the battery, but around 9v at the power supply side of the switch. Unless there's missing details, it shouldn't have anything to do with the starter being used. If the battery dropped that fast in voltage, I don't think it would start the other machine.

Oh I forgot to post the link to the battery cable/fuse setup. It doesn't show the inside so maybe I'm thinking of another machine, but up front they used the glass style, pretty sure they'd use the same type in the rear.

https://www.ebay.com/itm/1985-Honda-...p2047675.l2557

[Quintin]

You're right ps2fixer. I had switching the battery backwards. At this point check the connections especially the ground. Grounds are one of the most overlooked items in testing. Also unplug the regulator/rectifier. I've seen them cause some odd problems. Probably not but that will easily eliminate one possibility.

[ps2fixer]

Yea I was thinking the regulator for a bit, but it seems like it would cause the voltage drop in the whole system instead of only at the ignition switch.

[roonie]

DANG!..i wish folks would report their findings and post them....im having the exact same issue with me 250es

[ps2fixer]

DANG!..i wish folks would report their findings and post them....im having the exact same issue with me 250es

Do you have a thread about your machine? I'll try my best to help out. It would be super useful if you have a multi meter for testing. It has to be something simple, there isn't that much going on in these old machines.

[roonie]

i pmed you. I have a multi meter. didnt start a thread.