The quickest way to check the electrics of the solenoid is to check that
current is flowing in the circuit when it should, unfortunately just checking
for voltage doesn't eliminate breaks in the circuit between the gearbox switch
and through the solenoid. Locate the connector where the OD wire in the main
harness joins its partner in the gearbox loom, this will be amongst the mass
of connectors near the fusebox or on the firewall near the heater. On cars
with a dash or column manual switch there will be a yellow in the main harness
and a yellow/red in the gearbox harness. In cars with a gear-lever manual
switch, on UK cars it will be a 4-way bullet connector with white/browns in
the main harness and a white or white/brown in the gearbox harness. On North
American cars there is a white from the inertia switch to a 4-way bullet
connector which may or may not be in the main harness, then whites or
white/browns from there one into the gearbox harness for the OD and one into
the rear harness for the fuel pump.
Having found your connector ... part it and connect a test-lamp in its place.
With the ignition and manual switches on, and the gearbox in an OD gear, the
lamp should light. With all other combinations the light should be off. You
can use an ammeter, both my LH solenoids measure about 180 ohms which gives
about 70mA.
The above relates to the later LH-type OD, I don't know the details of the
D-type. It has an additional relay and vacuum switch and it is the relay that
supplies current to the solenoid, the manual switch just operates the relay.
However with the engine off but the ignition on you reputedly can hear the
D-type relay *and* the solenoid clicking as you operate the manual switch, but
not on the LH-type.
PaulH.
----- Original Message -----
From: mjanacek@snet.net
To: MG-MGB@yahoogroups.com ; MG-BBS
Sent: Thursday, September 02, 2004 8:23 PM
Subject: [MG-MGB] OD Trans Failure
Checked the OD switch for continuity, numerous cycles - OK
Checked that I have 12V across the switch connections when in 4th gear,
ignition on - OK
Check out the new British Cars Forum:
http://www.team.net/the-local/tiki-view_forum.php?forumId=8
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