Re: Wiring Harness

["jchapelhow" <chapelhow@xxxx>]

All.

Many thanks for your continued assistance, I have received several e-
mails of suggestions off-list and thought it was time for an update.

To recap, my electrical problems are that several of the gauges 
fluctuate with differing electrical loads, ie the turn indicators 
cause a `bounce' in the oil pressure reading. The central console and 
door lock warning indicators also dim when the indicators are used.

I have removed the instrument binnacle and cleaned all of the 
contacts, several of the bulbs were not fully seated therefore 
disrupting electrical pathways. At the moment the binnacle is still 
removed. 

I have temporarily unplugged all of the wiring connectors at the back 
right of the engine bay. The buzzer logic box panel has been removed, 
along with the intermittent wiper module, leaving just the flasher 
relay to `dangle' under the dash.

I have run a temporary ground connection from the engine bay ground 
point to the individual wires grouped near the left front wheel.

Now when I test the earth points either at the binnacle connector 
blocks or at the dashboard end of the buzzer box ground I am able to 
detect a voltage when circuits are turned on (0.7v side lights, 1.2v 
main lights, fluctuates to 1.45v when indicators are used), 
continuity tests also fail as soon as the ignition switch is moved to 
P1. Is this what everyone refers to as a floating earth? 

All new relays/fuses have been fitted (with all the connectors 
cleaned), the connectors to the ground by the front wheel look good 
and measure low resistance until `something' is energised by turning 
the key. This even happens with fuse 12 removed, the courtesy 
circuits (door lights) also seem to place a voltage on the ground 
cables.

All ideas welcomed.


John Chapelhow
DOC 19 : MMG 287W : `Boeing' 0737