Warning module Merc '97 150 hp

[bdc]

Horn stays on when ignition turned on. Test per service manual fails -bad module. Is there another test (bench) to confirm bad module?

 

[CharlieB]

Re: Warning module Merc '97 150 hp

Unplug sensor leads to the module and turn key on

Still continuous alarm, bad module.

Just normal self-test beep then something else is wrong.

 

[Texasmark]

Re: Warning module Merc '97 150 hp

Could have a shorted sensor. Son has a '95 150 and had the same problem. Found the OT sensor in the port water jacket partially shorted (tan wire)....enough to hear and see (dash light too) a failure. Replaced it, no more short and problem solved.

Mark

 

[j_martin]

Re: Warning module Merc '97 150 hp

There's a connector block with 2 screws on it on the starboard side above the switchboxes. One is 12 v to the oil warning module, and the other has 3 wires on it. One to the oil warning module, one to the overheat switch in the head, and one goes down to the cannon plug and on to the control box and alarm horn or light.

If you disconnect both the alarm module and the temp switch, and the alarm still sounds, there is a wiring fault. Otherwise, the one that sounds the alarm is the bad one. If it's the oil module, you can do the diagnostic above to isolate the sensor or the module itself.

hope it helps
John