View Full Version : Bad ignition switch?
So, finally got around to troubleshooting my low voltage issue at the dash. Here's what I found out:
1. 12.5V at the main harness coming in to the dash
2. 12.5V at the breaker panel
3. 12.5V coming to the ignition switch (orange)
4. 11.2V coming out of the ignition switch when 'on' (purple)
Had further 1V drop spanning across the gauges but cleared that up by tightening everything down.
This is all when the ignition is 'on' but engine not running. When the engine is running, I have 13.5 V everywhere. Doesn't seem to matter where I put the ground side of my meter, so I'm assuming my grounds are good.
Do I have a bad ignition switch? If not, what other suggestions?
Also have 13.5V at the back of the volt meter, but it reads a little less than 12. Guess I don't really care if the meter is totally accurate as long as I know what the margin of error is.
So, finally got around to troubleshooting my low voltage issue at the dash. Here's what I found out:
1. 12.5V at the main harness coming in to the dash
2. 12.5V at the breaker panel
3. 12.5V coming to the ignition switch (orange)
4. 11.2V coming out of the ignition switch when 'on' (purple)
Had further 1V drop spanning across the gauges but cleared that up by tightening everything down.
This is all when the ignition is 'on' but engine not running. When the engine is running, I have 13.5 V everywhere. Doesn't seem to matter where I put the ground side of my meter, so I'm assuming my grounds are good.
Do I have a bad ignition switch? If not, what other suggestions?
Also have 13.5V at the back of the volt meter, but it reads a little less than 12. Guess I don't really care if the meter is totally accurate as long as I know what the margin of error is.
Where did you ground the meter when you measured 13.5VDC? If it was on the motor, leave the meter on DC Volts and put one lead on the battery, the other on the main ground under the dash. If you read voltage, you have a bad ground. Disconnect the boat plug and make sure the pins/sockets are clean.
Where did you ground the meter when you measured 13.5VDC? If it was on the motor, leave the meter on DC Volts and put one lead on the battery, the other on the main ground under the dash. If you read voltage, you have a bad ground. Disconnect the boat plug and make sure the pins/sockets are clean.
The meter was grounded on the main ground coming to the back of the tach.
The meter was grounded on the main ground coming to the back of the tach.
Did you check continuity from that point to the battery negative? All voltages should be referenced to that point. If you see a difference (it would read higher) when you ground the meter at the battery, you have resistance on the negative to the dash. That's the reason I recommended looking at the boat plug (the one on the motor that connects it to the boat harness). Any resistance on the positive or negative wires will cause voltage drop and that can affect engine performance. If the coil's primary voltage is low, the secondary voltage will be low, too and that will affect spark intensity.
Jim: what should the voltage be at the boat harness? Measured it last night, have 12.5V when the boat is off. If the voltage is correct, what does a continuity test tell me?
Jim: what should the voltage be at the boat harness? Measured it last night, have 12.5V when the boat is off. If the voltage is correct, what does a continuity test tell me?
The voltage at the boat plug should be exactly the same as at the battery posts (not the cable clamps or ring terminals) if there's no resistance in the wiring. The battery posts are where everything is referenced. A continuity test will show where voltage drops are occurring. Remember these two things- Resistance on a wire is bad and P=IE (Power = Current x Voltage). Power is work, voltage is like water pressure and current is like flow rate. OK, three things. Pinch a hose (increase resistance) and the pressure & flow rate will drop downstream from the pinch, causing less work to be done. The dash harness is fed by the 10ga wire that's connected to the relay that activates the solenoid. I would bet that if you went from the battery to the dash wiring (positives and grounds) and loosened/cleaned/repaired every connection, your voltage would increase at the dash.
JimN: Think I already covered that. Voltage at my dash (primary harness, leading to the circuit board, back to the orange cable on my ignition switch) is exactly the same as my battery posts 12,5V. Voltage comes out the other side of my ignition switch ~1.3 Volts lower.
So I already traced Voltage from battery forward, thought I had identified the source of my drop. Question is, can a bad switch cause this or what other causes should I investigate before swapping out the switch. It doesn't seem to be an issue with clean contacts on the ignition switch as I've already cleaned and re-tightened those. I believe I've eliminated the ground as the issue, at least up to the back of the tach.
JimN: Think I already covered that. Voltage at my dash (primary harness, leading to the circuit board, back to the orange cable on my ignition switch) is exactly the same as my battery posts 12,5V. Voltage comes out the other side of my ignition switch ~1.3 Volts lower.
So I already traced Voltage from battery forward, thought I had identified the source of my drop. Question is, can a bad switch cause this or what other causes should I investigate before swapping out the switch. It doesn't seem to be an issue with clean contacts on the ignition switch as I've already cleaned and re-tightened those. I believe I've eliminated the ground as the issue, at least up to the back of the tach.
It's possible. Disconnect the ignition switch and check continuity from where the battery wire connects and the purple wire gets its voltage. If you see more than a fraction of an Ohm, it may be bad.
You show 12.5V a the harness to the switch- did you check it at the switch? If not at the switch, it's possible that the drop is between those two points.
Did you check before and after the safety switch?
12.5 V, at the ignition switch (orange wire)
11.2 V at the ignition switch (purple wire, ignition switch in the on position but boat not running)
13.5 V at both spots when boat is running
12.5 V, at the ignition switch (orange wire)
11.2 V at the ignition switch (purple wire, ignition switch in the on position but boat not running)
13.5 V at both spots when boat is running
I think that as long as you don't have problems with accessories dying untimely deaths and performance issues, it should be OK.
Perfect World voltages and resistance readings are nice, but it's hard to have them in all cases.
The symptom has been solved, which was my PP rebooting often because voltage was too low. Cleaned up all the behind the dash connections, now have 11+ Volts at the tach/PP and it seems to be working. I'll probably leave well enough alone.