Headlight saga continues

[birdshill123]

I had posted previously about my poor low beam headlights. I got lots
of good advice and great schematic on rewiring the lights with Bosch
relays. Today I checked the voltage at the lights. With the dims on I
noticed a slight amount of light coming from the inside (bright )
headlamp. I checked the voltage between the black (should be ground)
and the red(low) . 10.8 volts. The green and black on that same lamp
show 12.9 volts. I do not have section 10 in my blue box with the
wiring diagram but I do have the BB blueprints, albeit faded. They show
relays for all the headlamps. Same #'s as the bosch(85,86,87,30). There
is a notation on the print that the relays were added some time in1987.
The headlamps are not shown on the print but the wires go from the
relays to a junction box that is in the front left side battery
compartment. I would like to check the voltage at the relays and trace
the ground wires. Where are these relays located? Behind the grill. I
am thinking maybe a bad ground somewhere. Any help appreciated.

Bruce

[one_dusty_hoot]

Bruce,
You can determine if you have a bad ground without the
location of the relays by one of two ways.

1.) With your voltmeter measure from the wire that should be
ground to battery ground. If you read 2 Volts then you DO have
a bad ground. If you read 0 Volts then the ground is good.

2.) Or, Connect a wire from known ground, battery negative
preferred, touch the other end to the lamp side that is supposed
to be ground. If the headlight brightens, bad ground, if not,
ground is good.

If the ground is good, problem is in 12 V supply.

I would believe that the 12 VDC supplies both high beam and
low beam from the same common point. This suggests that the
possible cause may be in the contact resistance of the relay.

Relays do have a wiping action but they can also develop over
time a contact resistance.

I do not know where the hi/low beam relays are myself but do
see the relays noted on a BB schematic as if the schematic was
updated. It may be possible with the headlights ON switching
from high to low beam listening for the relays being energied.

If hearing the relays click in is not possible, then with the
low beams ON remove relays one by one till the light goes out.

Otherwise unless someone knows the location, the only method
that comes to mind is tracing back from the lamp or forward
from the headlight switch.

When you find it label it for future need ;>)

Bob Janes, 87 FC35, Greenville, SC



--- In WanderlodgeForum@yahoogroups.com, "birdshill123"
wrote:
>
> I had posted previously about my poor low beam headlights. I got
lots
> of good advice and great schematic on rewiring the lights with
Bosch
> relays. Today I checked the voltage at the lights. With the dims
on I
> noticed a slight amount of light coming from the inside (bright )
> headlamp. I checked the voltage between the black (should be
ground)
> and the red(low) . 10.8 volts. The green and black on that same
lamp
> show 12.9 volts. I do not have section 10 in my blue box with the
> wiring diagram but I do have the BB blueprints, albeit faded. They
show
> relays for all the headlamps. Same #'s as the bosch(85,86,87,30).
There
> is a notation on the print that the relays were added some time
in1987.
> The headlamps are not shown on the print but the wires go from the
> relays to a junction box that is in the front left side battery
> compartment. I would like to check the voltage at the relays and
trace
> the ground wires. Where are these relays located? Behind the
grill. I
> am thinking maybe a bad ground somewhere. Any help appreciated.
>
> Bruce
>

[pattypape]

Bruce,

I do not have this problem, so I have not investigated this
circuit, sure sounds like a bad ground or the female plug into
the headlamp. I do not know where these relays are located,
but there is a panel behind the grill above the driver side
headlight. This gives access to relays, and the parts forward and
below the foot pedals, You may be able to see or hear the relays
energize from the driver floor area forward of the pedals and
steering wheel columne.

Bill 88 FC


--- In WanderlodgeForum@yahoogroups.com, "birdshill123"
wrote:
>
> I had posted previously about my poor low beam headlights. I got
lots
> of good advice and great schematic on rewiring the lights with
Bosch
> relays. Today I checked the voltage at the lights. With the dims
on I
> noticed a slight amount of light coming from the inside (bright )
> headlamp. I checked the voltage between the black (should be
ground)
> and the red(low) . 10.8 volts. The green and black on that same
lamp
> show 12.9 volts. I do not have section 10 in my blue box with the
> wiring diagram but I do have the BB blueprints, albeit faded. They
show
> relays for all the headlamps. Same #'s as the bosch(85,86,87,30).
There
> is a notation on the print that the relays were added some time
in1987.
> The headlamps are not shown on the print but the wires go from the
> relays to a junction box that is in the front left side battery
> compartment. I would like to check the voltage at the relays and
trace
> the ground wires. Where are these relays located? Behind the
grill. I
> am thinking maybe a bad ground somewhere. Any help appreciated.
>
> Bruce
>