Third brake light out mystery- 96 Buick Century

My head is sore from all the head scratching- what am I missing?
The third brake light doesn't light, the left and right brake lights are fine. First, I put a brick on the brake pedal.Open the light, replace the 2
bulbs with 1156's like the owners manual says- doesn't work. Wait- on the housing it says to use 1141's, try that, still doesn't work. Check the voltage- I only get power when the ignition is on, and I only get 6 volts. I try the voltmeter on a regular brakelight, get 12 volts anytime the pedal is depressed. Anyone know what I'm doing wrong? Thanks!
--
John M. Darnielle
Remove obvious phrase from address to e-mail me
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Throw a ground to the socket and see what happens.
--

-Mike-
snipped-for-privacy@alltel.net
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Are all the rest of the lights working ok , signals ,4 ways etc. ? This could be the start of signal switch problems. Very common in those cars. Been there myself twice.
On Wed, 28 Mar 2007 21:41:02 -0600, "John M. Darnielle"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi! All the other lights work great. I get the same 6 volts measuring from contact to contact as I do from hot contact to ground. ???
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hows the connection where the wire harnesses plug together? Clean?
h
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi- Yes, and just to make sure I cut it tested voltage there as well, got same 6 volts. I put it back together with wire nuts. I'm still stumped.
John

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Most likely cause of reduced voltage is a poor connection, which causes high resistance. You may need to follow the wire to the front of the car to find the problem area. A wiring diagram and a good understanding of how to diagnose eletrical problems are needed. Electrical problems can be extremely hard OR very easy to fix but you won't know which one it is until you actually find the problem. My advise would be to check the easiest connections you can get to at each end of the wire in question first. If you don't find the problem at either end you will have to follow the wire from one end to the other, which may not be as easy as it sounds.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Did you try to apply a good solid ground to it yet? Bad grounds are the leading cause of bizarre lighting problems in cars. Low voltage like you are seeing is quite common as circuits feed back when grounds are bad.
--

-Mike-
snipped-for-privacy@alltel.net
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi- I think I'll try that next. I didn't ground it because I was still getting 6 volts when I measured from hot wire to a good ground, as well as from hot wire to ground wire. If that doesn't work I'll try tracing the circuit forward. Thanks!
John

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sorry - did not realize you had measured from the hot lead to a known good ground. Going to another known good ground won't help you much.
--

-Mike-
snipped-for-privacy@alltel.net
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks to everyone who chipped in to help solve this- it turned out to be the brake light switch.
John

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.