 Parking brake warning light switch |
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| jeremiah98125 |
 Mar 1 2010, 01:41 PM
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#1
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jr  Group: Members Posts: 37 Joined: 11-November 09 From: seattle, wa Member No.: 11,031 Region Association: Pacific Northwest  |
I've been trying to fix my brake warning light switch, it flashes all the time. Occasionally I could get it to go out by slamming the P-brake all the way down, but it would eventually turn back on again. So I figured it was the switch under the P-brake handle. I pulled the switch out and it doesn't seem to do anything, but it looks fine to me?? The wire that leads to it looks okay too.. Is there a way to test the switch?
I was thinking it could be the m/c reset button, but doesn't make sense if I could get it to turn off with the P-brake before.. |
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Replies(1 - 8)
| zonedoubt |
Mar 1 2010, 02:02 PM
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#2
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Canadian Member Group: Members Posts: 668 Joined: 14-May 03 From: Vancouver, BC Member No.: 696 Region Association: Canada |
Make sure the switch is grounding to the chassis. Test with a multimeter.
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| SirAndy |
Mar 1 2010, 02:13 PM
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#3
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Resident German Group: Admin Posts: 41,656 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
Take the wire off the switch and connect it to ground ...
If the light goes out, your switch is bad or does not ground correctly when mounted. (IMG:style_emoticons/default/shades.gif) Andy |
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| zymurgist |
Mar 1 2010, 02:22 PM
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#4
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"Ace" Mechanic Group: Members Posts: 7,411 Joined: 9-June 05 From: Hagerstown, MD Member No.: 4,238 Region Association: None |
This is relevant to my interests. (IMG:style_emoticons/default/cat.gif)
Babydoll has this problem... except the wire going to the switch is broken. It was connected at one time... does this wire break out from the center tunnel? |
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| jeremiah98125 |
Mar 1 2010, 02:27 PM
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#5
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jr Group: Members Posts: 37 Joined: 11-November 09 From: seattle, wa Member No.: 11,031 Region Association: Pacific Northwest |
QUOTE(zymurgist @ Mar 1 2010, 12:22 PM)  This is relevant to my interests. (IMG:style_emoticons/default/cat.gif) Babydoll has this problem... except the wire going to the switch is broken. It was connected at one time... does this wire break out from the center tunnel? Part of the problem is the top of the switch that makes contact with the bottom of the p-brake handle is worn down, but also I took the wire off the switch completely and the light gets dimmer and blinks slower, then when I ground the wire the light gets brighter and blinks faster at the normal rate. Does this mean the wire is partially grounding somewhere or should I investigate the m/c switch as well? |
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| tradisrad |
Mar 1 2010, 03:19 PM
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#6
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Senior Member Group: Members Posts: 985 Joined: 11-September 06 From: San Mateo, CA Member No.: 6,815 Region Association: Northern California |
On the later model hand brake there is a return spring that connects from a tab on the cable to the fire wall. This spring should keep the hand brake "down" and puts pressure on the switch keepin the light off.
On my '70 there is no return spring and I found that tightening the cables I was able to keep my light off. Becareful to avoid over tightening. I think the light goes on when grounded. |
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| SirAndy |
Mar 1 2010, 03:26 PM
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#7
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Resident German Group: Admin Posts: 41,656 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(tradisrad @ Mar 1 2010, 01:19 PM) I think the light goes on when grounded. You're correct, i got that mixed up. When connecting the wire to ground, the light should come on. The switch keeps the connection open when the handle is down and closes the circuit when the handle is up. (IMG:style_emoticons/default/shades.gif) Andy |
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| jeremiah98125 |
Mar 1 2010, 03:40 PM
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#8
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jr Group: Members Posts: 37 Joined: 11-November 09 From: seattle, wa Member No.: 11,031 Region Association: Pacific Northwest |
I pulled out the multimeter and checked continuity to ground. With the wire disconnected, it goes up about 1/2 way. Would this mean the wire is bad and rule out the m/c switch? Can I run a new wire straight to under the dash where it hooks up on the gauge? From the P-brake lever, it looks like the wire goes into a hole right with one of the cables and then it disappears.. seems like it could of gotten pinched back there?
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| tradisrad |
Mar 1 2010, 04:44 PM
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#9
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Senior Member Group: Members Posts: 985 Joined: 11-September 06 From: San Mateo, CA Member No.: 6,815 Region Association: Northern California |
The wire probably meets up with the wire harness in the center tunnel.
Disconnect the wire at the bulb & switch and remeasure the continuity from both ends to ground (you should have an open circuit, infinite resistance) and end to end (closed circuit, low resistance like 1 Ohm). You could be grounding at the bulb/socket/gauge |
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