2012 F90LA Tiller starting issues

[Murphyflyer]

Here are the symptoms:
Turn the Key to the on position and the fuel pump stays quiet.
Turn the key to the start position and nothing happens.
There is 12 volts at the starter and at the starter relay.
There is 12 volts at the trim relay and trim works fine
This began as an intermittent problem that I initially chalked up to battery/connection issues. Now it won't make a peep.

What I have checked so far:
Battery
All connections from battery to engine
All fuses in the fuses block are good (checked with multi meter)
Neutral switch has continuity
Engine stop lanyard switch works properly
Starter relay changed and verified
The main and fuel pump relay checked as per the service manual.

I am not sure how to check the ignition switch or the harness for continuity.

Any ideas? Thanks

[robert graham]

Maybe remove/check the connections on the side of the starter....could your battery cables be corroded internally where it's not visible/obvious?....

[rodbolt17]

check that you have 12v to the switch (red wire) and 12V leaving the switch(yellow wire).
sounds like the ECU isn't receiving a key on signal that wakes up the ECU and then powers up the main relay.
it also takes 12V on the brown wire at the keyswitch to toggle the start relay that then toggles the starter solenoid.

pretty simple stuff actually.

[Murphyflyer]

Thanks Rodbolt. I have checked the switch. There is 12 volts on the red wire. Only .5 volts on the wire when the switch is on and .5 volts when the switch is in the start position. I will get a new switch and report the results.

Thanks RG. I have good voltage as I went over everything again.

[rodbolt17]

why bother with the switch?

do a voltage drop test from the starter positive to the ign switch red and find the bad connection/wire.

[Murphyflyer]

I wasn't very clear in describing the results of my test.

Red wire has 12v at the switch.
Yellow wire has .5v with switch on.
Brown wire has .5v with start keyed.

[99yam40]

where was the neg lead while this testing was happening?

I believe Rod was referring to your battery connections cannot hold up to current flow but are OK with no load.

But I have been wrong in the past

[boscoe99]

A lack of 12 volts on the yellow wire with the key in the on position and a lack of 12 volts on the brown wire with the key in the start position indicates a problem with the switch or a connection of the red wire to the switch.

This would explain the fuel pump not running momentarily when the key is first turned to the on position and would explain the starter motor not operating.

As a test, just jumper the red wire to the yellow wire at the key switch and see if the pump runs. With the red wire jumpered to the yellow wire also jumper the red wire to the brown wire and see if the starter motor engages.

What ever voltage is see on the red wire should be seen on the yellow wire and the brown wire when the key switch is in the appropriate position.

[Murphyflyer]

I jumped the red to yellow at the switch and the fuel pump started up as normal.
I then jumped the brown as well and the starter turned.
New switch is on order.
I will report when installed.

Thanks guys!

[Murphyflyer]

I replaced the suspected ignition switch. All is good now. Thanks to all for your help.

[boscoe99]

Thanks for the feedback.