brake light problem

If still nothing...check owners maual, again, for fuses under hood ( I know
newer trucks have), check brake light switch is getting power and working,
if it is probably multifunction signal switch in steering column bad .
R
 >> Stay informed about: brake light problem 

There is a block of fuses under the hood, close to the master cylinder,
and inside, there is a socket for the brake light fuse/relay - as well
as a sticker inside the cover that says where it "should" be. Now if I
look into the fuse block, there is only metal connections on one side
of the pins where the fuse/relay would fit into it - so I don't think
there was ever one in there from the factory. There was probably an
option on this truck or a larger truck that wasn't installed on mine.

The trailer wiring harness is the T-type connector that plugs into the
factory wiring harness at the rear of the vehicle. I will unplug it
and check for power there, but I think the problem is likely something
under the dash.

The brake light switch is really in a tight spot - not looking forward
to trying to get that off. Also, is there a way to determine if the
problem is the brake pedal switch or the signal switch in the steering
column?
 >> Stay informed about: brake light problem 

On the brake switch, usually orange is hot, and white gets power when the
brake pedal is pressed. Maybe you could make a probe wire to get in the back
of the plug to test the wires with your meter. You would think/hope if the
trailer had a problem with wiring, it would just pop a fuse in your truck.
But tempoarily remove the T harness put back to factory and hope for the
best. But it seems failure in the steering column on the signal/flasher
switch is very common, GM just had a big recall on this in newer
vehicles.....R


"SuperDave" <dgargan DeleteThis @gmail.com> wrote in message
news:1132010765.577360.79290@f14g2000cwb.googlegroups.com...
> There is a block of fuses under the hood, close to the master cylinder,
> and inside, there is a socket for the brake light fuse/relay - as well
> as a sticker inside the cover that says where it "should" be. Now if I
> look into the fuse block, there is only metal connections on one side
> of the pins where the fuse/relay would fit into it - so I don't think
> there was ever one in there from the factory. There was probably an
> option on this truck or a larger truck that wasn't installed on mine.
>
> The trailer wiring harness is the T-type connector that plugs into the
> factory wiring harness at the rear of the vehicle. I will unplug it
> and check for power there, but I think the problem is likely something
> under the dash.
>
> The brake light switch is really in a tight spot - not looking forward
> to trying to get that off. Also, is there a way to determine if the
> problem is the brake pedal switch or the signal switch in the steering
> column?
>
 >> Stay informed about: brake light problem 

OK, I took the column apart, and unmounted the multifunction switch.
You can actually unclip the plastic overtop of the wire terminals going
into the switch and use a tester or multimeter to test. I see the
flashing power on a pair of terminals when the turn signal lever is
clicked, so I assume those wires are also the wires that go hot when
the brake switch is pressed. Also, on the white wire, I can see power
there when I depress the brake pedal, but nowhere do I see outgoing
power to the tail lights. I am pretty sure this switch is the cause of
my problems.

GM dealer quoted me $380 for the multifunction switch!!! At
monsterautoparts.com it's $260, and at gmpartscheap.com it's $248.
Quite a spread so far... so I checked locally - napa wants $236,
Advance Auto Parts wants $175, and at Pep Boys it's $150. This does
look like a more expensive part - it's got the turn signal arm w/cruise
and wiper connections attached to it, as well as the hazard light
switch is built into it.... but I think that $380 is way out of line.

I asked each store plenty of questions, and some seem like they know
what I'm talking about, some of them seem like they have never seen a
car before. Some of them ask me if I have cruise, and tilt steering
(the dealer did, and told me there was a difference) and some of them
don't bother to ask and when I prompt them they tell me there's just
the one switch available.

Looks like I'll have to take mine around with me to these places and
compare so that I get the right part.

SuperDave
 >> Stay informed about: brake light problem 

Did u try a Salvage Yard ??




SuperDave wrote:
> OK, I took the column apart, and unmounted the multifunction switch.
> You can actually unclip the plastic overtop of the wire terminals going
> into the switch and use a tester or multimeter to test. I see the
> flashing power on a pair of terminals when the turn signal lever is
> clicked, so I assume those wires are also the wires that go hot when
> the brake switch is pressed. Also, on the white wire, I can see power
> there when I depress the brake pedal, but nowhere do I see outgoing
> power to the tail lights. I am pretty sure this switch is the cause of
> my problems.
>
> GM dealer quoted me $380 for the multifunction switch!!! At
> monsterautoparts.com it's $260, and at gmpartscheap.com it's $248.
> Quite a spread so far... so I checked locally - napa wants $236,
> Advance Auto Parts wants $175, and at Pep Boys it's $150. This does
> look like a more expensive part - it's got the turn signal arm w/cruise
> and wiper connections attached to it, as well as the hazard light
> switch is built into it.... but I think that $380 is way out of line.
>
> I asked each store plenty of questions, and some seem like they know
> what I'm talking about, some of them seem like they have never seen a
> car before. Some of them ask me if I have cruise, and tilt steering
> (the dealer did, and told me there was a difference) and some of them
> don't bother to ask and when I prompt them they tell me there's just
> the one switch available.
>
> Looks like I'll have to take mine around with me to these places and
> compare so that I get the right part.
>
> SuperDave
>
 >> Stay informed about: brake light problem 

No, I didn't try a salvage yard. Depending on the item, I sometimes
buy used, but in this case I'd rather just buy a new one. I ended up
buying it from Advance Auto and that did the trick.

The switch was the problem, so replacing it did the trick. Now when I
depress the brake pedal, I can see power on the white wire coming into
the switch, and also on both wires going out of the switch to the tail
lights as well. (One is purple, and I "think" the other one is green)

SuperDave
 >> Stay informed about: brake light problem 

Dave, I'm having the same issue on my 93 GMC. How much of a pain is it
to replace? I take it you pull the steering wheel and disassemble where
the switch goes? Do the wires run all the way down the column? Any
words of advise before I tackle this? Not looking forward to it, but I
can't drive the truck with no brake lights...

Thanks!


SuperDave wrote:
> No, I didn't try a salvage yard. Depending on the item, I sometimes
> buy used, but in this case I'd rather just buy a new one. I ended up
> buying it from Advance Auto and that did the trick.
>
> The switch was the problem, so replacing it did the trick. Now when I
> depress the brake pedal, I can see power on the white wire coming into
> the switch, and also on both wires going out of the switch to the tail
> lights as well. (One is purple, and I "think" the other one is green)
>
> SuperDave
 >> Stay informed about: brake light problem 

What let go on the old one..anything melted or contacts just worn out?...R


"SuperDave" <dgargan RemoveThis @gmail.com> wrote in message
news:1132554046.847337.27690@g49g2000cwa.googlegroups.com...
> No, I didn't try a salvage yard. Depending on the item, I sometimes
> buy used, but in this case I'd rather just buy a new one. I ended up
> buying it from Advance Auto and that did the trick.
>
> The switch was the problem, so replacing it did the trick. Now when I
> depress the brake pedal, I can see power on the white wire coming into
> the switch, and also on both wires going out of the switch to the tail
> lights as well. (One is purple, and I "think" the other one is green)
>
> SuperDave
>
 >> Stay informed about: brake light problem 

I don't really know what happened to the old one. I'm assuming broken
or burnt contacts inside, because externally, it looks fine.

I know the interior on your 1993 is a little different, but I can
describe how much work it is on a 96. I didn't have to pull the
steering wheel, just disconnect the airbag wiring and a good part of
the dash. The cover of my column splits in half, top and bottom. The
bottom comes off with 2 screws, and then there are 2 screws inside the
column holding the top part on. The top part wouldn't come off very
far because it doesn't slip over the collar of the ignition switch..
I'm sure there is a way to get the outer part of the ignition switch to
come off, but I don't know how. Then the upper front part of the dash
has to come off, as well as the bottom part of the dash - these are
fairly simple to get off if you're careful - a few screws and the rest
is friction fit.

The multifunction switch has 2 screws holding it down, which are very
tight to get at if you don't take the steering wheel off - one faces up
and the other faces towards the driver, with only about an inch or so
of clearance between it and the steering wheel. I actually used a hex
screwdriver bit that just fit in between and then used a tiny wrench to
turn it. I really didn't want to mess with the airbag stuff inside the
steering wheel. Then the wiring runs about a foot or so down the
column and into a large connector under the dash. This connector had a
bold in the middle holding it all together. Once you get this bolt
undone, the connector comes away and can be split into 3 parts. You
can then remove the switch and wiring completely.

I found that the 3rd high mount brake light actually gets power
directly from the brake switch itself - seems like it's the only thing
that doesn't run through the multifunction switch. I was really
puzzled when that brake light worked, and the regular brake lights did
not. The 4 way flasher hazard lights no longer working also kinda
tipped me off that it wasn't a wiring problem.

Hope that helps.

SuperDave
 >> Stay informed about: brake light problem