2010 Tahoe Q5i 4.3L Mercruiser Carb. No power to ignition switch.

[Alerma]

No power to ignition switch.

 

[alldodge]

No power to ignition switch.

Meaning when key is turned the gauges do not turn on

Get a voltmeter and start at the battery, to the starter, to the 50 amp breaker, to the Red/purple wire at the key

 

[Alerma]

I have tested the 90 amp fuse the reset fuse, checked continuity on both ignition switch and kill switch and also have replaced a 20 fuse that took me forever to find on top of motor. All tested good but still cant forgive out why I cant get any power to ignition switch. On any wire on switch. Don’t know where to look any more.

 

[GA_Boater]

Howdy.

Is this a new problem or one that just popped up?

Does the trim and tilt work on the TnT switch?

 

[QBhoy]

Try testing it with the earth from elsewhere, other than the switch and see if you get power.

 

[tank1949]

Make sure battery (s) fully charged. With battery selector set to specific battery, jump your starter (screw driver, wrench, pliars, etc.). If starter will not engage, check for green oxidation around lugs, and GROUND. If good, use milti-meter to check voltage at ignition. If ignition is not getting or providing 12+ volts back to starter "noid," it will not engage starter and crank.(be sure to pull coil wire first) . I had red main battery/motor cable develop crack decades ago on outboard, which gave similar results. Cable had dissolved under plastic shield. You may have to buy a couple of jump electrical leads for you multi-meter to use as ground. My multi-meter only has 3' long leads. You may need longer.

 

[Bt Doctur]

1 test at the battery
2 test from + battery to block
3 test from neg battery to to alt output post
4 verify 90 A fuse link at starter (if equipped)
5 verify main engine harness plug

 

[Alerma]

GA_Boater, This is new. Boat has been solid for years. We where in the water all day with no issues and when we decide to pull anchor and head home could not get ignition switch to do anything. Everything else as far as electrical was working. Just could not get switch to turn on boat.

 

[Alerma]

QBhoy, I have texted with a light tester and do not have any power on all three wiring on ignition switch. I noticed on other forum about a fuse located behind engine and after hours of searching I found and the 20 amp fuse was blow. I replaced and still no power to ignition switch.

 

[Alerma]

Thank you guys so much for responding. Im getting ready to leave on vacation for a week and will try other suggestions when I return.

 

[Alerma]

I have power at battery, I have power going to starter see pic. I think. I have power at the top fuse labeled W.P.D fuse. I’m not sure what the Purple and yellow wire or for that go to the starter but I have no power there

 

[Alerma]

Where does the red wire on the ignition switch get its power from?

 

[Grub54891]

That white box on your first Pic is a fuse also. Check for power there on the outgoing side.

 

[alldodge]

Where does the red wire on the ignition switch get its power from?

The Red/Purple wire on the ignition comes from the 50 amp breaker on the motor. Should be a red button type breaker that just gets poped out when tripped, and pushed in to reset.

Are you measuring voltage with a meter or using a test light?

 

[Alerma]

Just using a test light.

 

[alldodge]

You need a voltmeter. A test light will light with much less then 12V, it is a good tracer though.

Follow the wiring in the diagram. You should see voltage on both sides of the 50 amp breaker and at ignition

 

[Fun Times]

Also see if you have 12v power at the orange wire off the back side of the alternator...That will quickly tell you if the 90 Amp fuse is good or not down by the engine starter...Also with the key switch to "on", try wiggling the main 10 pin wire harness on the engine to see if you regain power up at the helm gauges.

 

[Bt Doctur]

per the diagram in post 16, locate "C" jump the 2 large posts, starter must spin. Check the ground cable connection at the block

 

[tank1949]

Just using a test light.

light testers are better than nothing but a good multi-meter is much beter

 

[Brosport05]

Hey guys I am having this same exact problem. I have checked everything that you all recommended. I still cannot figure it out and have come to the conclusion that it’s the icm. Any thoughts?