Whilst a short can be of insufficient current to blow the fuse, but of
sufficient current to cause a slightly dodgy connection between it and the
voltage source to go open-circuit or almost so, if the problem were in the
turn signal switch it would be there all the time and not just when you
operate the brakes. If you have 12v on the hot side of the brake switch
normally, but it drops to zero or nearly so when you operate the brakes,
then there is either a short (or nearly so) on the brake lights plus a weak
connection between the switch and the battery, or simply a bad connection.
If the brake lights work by connecting the lights side of the brake switch
direct to the battery, without smoking your linking wire, then you can
discount a short at the lights. Which leaves the bad connection. Do the
turn signals and running lights work with the brakes on? If so, and if the
brake light switch gets its 12v supply from the turn switch as you imply,
then the fault must be between the two switches. It could be where a wire
joins to a connector or a connector to a component. If the turn signals
fail as well then the problem lies between the turn switch and the battery.
PaulH.
----- Original Message -----
From: "Roger Wilt" <rdwilt@pol.net>
To: <mgs@autox.team.net>
Sent: Thursday, August 19, 2004 3:05 AM
Subject: TD brake light saga better but continued
> Well, I found out the brake hydraulic switch was going bad but not
> completely bad... yet. Got a new Moss switch anyway - still no brake
lights.
> Was able to determine that everything works fine until I hook up the brake
> switch wire which goes to the turn signal box (a lever action "ALLSTATE"
> brand). then lost current across switch when brakes engaged. Took apart
the
> turn signal box, disconnected the brake switch wire, and ran a new wire
from
> the cold contact on the brake switch to the rear wire turn signal, hit the
> brakes and a brake light lit up!!!
>
> My current theory is there is a short circuit to ground in the turn signal
> switch but somehow preserved running lights and turn signals. Whew! I'm
> going to further dismantle the switch this weekend and hope for a cure. If
> not, I will be asking for direction on a new brake light / turn signal
> switch / setup.
>
> Any other thoughts are appreciated.
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