2000 Mercury 200 EFI - Tach stopped working

[JohnM64]

# 0T067993 on a 2000 Tr-20.

Yesterday, the tach just stopped working. It appears to have power, the needle moves when ignition is cycled, but no result when engine running.

I've not looked into it any further, just looking for any input on diagnostics - your help is appreciated.

[leonreno]

Check your regulators for burnt spots or burnt wires, you should have two. This only pertains if you have regulators, if your motor has an alternator then it will be different.

[MikeKz]

Years ago, had a cousin hook up main battery backwards (+ on -, - on + wires, it cooked my fuseable link. On my 3L the tach stopped working. $60 for a new one.

[JOE54]

theres a gray lead on regs that is connected to wire harness unplug wire and connect to other reg gray wire tach circuit may be bad in one reg , if it works replace reg , CHECK ALL FUSES FIRST ON MTR

[JohnM64]

Thanks Joe. I spent some time last evening researching, and what I've read concurs with your response.

I did get to inspect the regulators, and there is no discoloration or apparent damage. I will check the regulator fuses, and try swapping gray tach lead from one regulator to another.

[JOE54]

[JohnM64]

Jumped tach lead to 2nd regulator, tach works, 1st regulator tested bad. Two new regulators ordered.

[JOE54]