1989 third tailight
Burning Brakes
Joined: Dec 2008
Posts: 1,021
Likes: 7
From: Morgan Hill and Marina California
MAYBE the switch. It's a DPST switch, one side (light blue wire) supplies
power to the CHMSL (third brake light), the other side (white wire)
to the other brake lights.
See if you get power to the blue wire with the brake pedal depressed
a bit. Or jump from the orange wire to the light blue wire at the
switch and see if the CHMSL comes on.
Other possibilities are a bad connection on the light blue wire, and
a bad ground.
All of the above from the '87 FSM. '89 might be different.
Chuck
power to the CHMSL (third brake light), the other side (white wire)
to the other brake lights.
See if you get power to the blue wire with the brake pedal depressed
a bit. Or jump from the orange wire to the light blue wire at the
switch and see if the CHMSL comes on.
Other possibilities are a bad connection on the light blue wire, and
a bad ground.
All of the above from the '87 FSM. '89 might be different.
Chuck
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
MAYBE the switch. It's a DPST switch, one side (light blue wire) supplies
power to the CHMSL (third brake light), the other side (white wire)
to the other brake lights.
See if you get power to the blue wire with the brake pedal depressed
a bit. Or jump from the orange wire to the light blue wire at the
switch and see if the CHMSL comes on.
Other possibilities are a bad connection on the light blue wire, and
a bad ground.
All of the above from the '87 FSM. '89 might be different.
Chuck
power to the CHMSL (third brake light), the other side (white wire)
to the other brake lights.
See if you get power to the blue wire with the brake pedal depressed
a bit. Or jump from the orange wire to the light blue wire at the
switch and see if the CHMSL comes on.
Other possibilities are a bad connection on the light blue wire, and
a bad ground.
All of the above from the '87 FSM. '89 might be different.
Chuck
Run a jumper wire from a 12v source to the blue wire and see if the CHMSL comes on. The usual culprit is the switch. There are 4 bulbs in the housing so the chances of all being burned out would be slim.
3rd Gear
Joined: Jul 2007
Posts: 3
Likes: 0
So if it isn't the switch or the bulbs, any other common areas to look for? The CHMSL on my new-to-me 88 convertible doesn't work, and I have already replaced the bulbs (they were all burnt out - and ARGH it's a pain to change them on a 'vert) and the switch - still nothing.
My FSM is ordered and on the way, but I'm impatient to start getting things fixed
I will try jumping the orange to blue wires tomorrow, but not expecting that to work as I already put in a new switch.
Any thoughts or suggestions would be appreciated!
Pierre
My FSM is ordered and on the way, but I'm impatient to start getting things fixed
I will try jumping the orange to blue wires tomorrow, but not expecting that to work as I already put in a new switch.
Any thoughts or suggestions would be appreciated!
Pierre
Racer
Joined: Oct 2011
Posts: 394
Likes: 6
From: woodstock ga
Default 3rd brake light
89...My 3rd brake light was out, so after removing i found all 4 bulbs with burnt spots on them. after replacing with new bulbs at $7.99 each it still did not work. my volt meter showed 11.98 volts to the light rack but it would not light my test light. so i started tracing back to the source of power and found that the brake light switch at the brake pedal was bad. i replaced the brake light switch for $13.00 and NOW IT WORKS. hope this helps someone that may have similar issues.
89...My 3rd brake light was out, so after removing i found all 4 bulbs with burnt spots on them. after replacing with new bulbs at $7.99 each it still did not work. my volt meter showed 11.98 volts to the light rack but it would not light my test light. so i started tracing back to the source of power and found that the brake light switch at the brake pedal was bad. i replaced the brake light switch for $13.00 and NOW IT WORKS. hope this helps someone that may have similar issues.
3rd Gear
Joined: Jul 2007
Posts: 3
Likes: 0
An update to the adventure...
Hit the brake pedal and... NOTHING. Still just the outer lights and no CHMSL... ugh.
I guess next steps will be to:
- I jumped the orange to blue wires at the brake switch, still nothing.
- I checked the continuity of the blue wire from the brake switch to the light bar, and found that somewhere along the way the wire is broken - UGH.
- For the heck of it, I ran a 12v source directly to the light bar and confirmed the lights work (when receiving power, go figure!
) - Still without my FSM (ETA mid-next week), I attempted to trace the wire from the switch to the light bar... finally finding the bundle running down the passenger side of the car and passing under the carpet under the softtop storage area.
- Found that water must have pooled in this area and all of the connections were corroded. At one of the connectors, the blue wire was disconnected (and the orange and white - I wonder what those are for??).
- Didn't have the spade connectors handy to repair the connector properly, so temporarily connected each of the wires directly (I will rebuild the connector later when I have the parts)
Hit the brake pedal and... NOTHING. Still just the outer lights and no CHMSL... ugh.
I guess next steps will be to:
- Retest the continuity of the blue wire from the switch to the light bar
- Check the ground to the light bar.
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