'90 Accord Brake Lamp indicator

1990 Honda Accord 4 door. Canadian edition (DLR.,etc.). Recently the dash
indicator for "Brake Lamp" has been illuminating constantly (was
intermittant for a short time). All brake lamps seem to be operating
properly, including HighMount, however indicator is lit whenever vehicle is
in motion.(i.e. no park brake). Anyone have any suggestions as to the
cause/reason? Anyone have a wiring diagram as to how this magic all takes
place? Anyone with a suggestion other than remove dash indicator lamp? I
know you guys are really sharp on these things and my daughter will really
appreciate not having to look at that little red lamp all the time. Thankyou
to each and all of you who have taken the time to read this post and give it
your consideration. I hope we will come up with a solution before I have to
take it to the dealership for a $100+ dollar fix. Looking forward to your
reply and thanks again......bob

 

My 91 EX-R does that every once and a while. Yank out the bulbs and then put
them back. It just wants some attention from you.

 

Check all the bulbs carefully once again. Some Accords have two side by
side brake light bulbs on each side and it is easy to miss one. The 90
Accord hatchback was this way, not sure about the sedan.

The current to each bulb runs through the coil of a small relay. If
there is current flowing, the relay closes. If a bulb is broken, no
current flows, and the relay does not close. There is one relay for each
light bulb, and all the relay contacts are wired in series. Thus, if any
bulb is broken, there will be no continuity through the chain of relay
contacts.

I believe the '90 had the relays mounted in two modules, on for the left
and one for the right hand side. The modules were mounted somewhere in
the trunk. The two modules look very similar, but may not be
interchangeable; In some Accords one side had a diode whereas the other
side did not. On other Accords the two modules were identical and
interchangeable.

One of the two modules (but not both) require a ground connection. If
this ground connection is missing / intermittent / high impedance you
can get false brake bulb alarms.

I found on my hard disk a ZIP file with Accord wiring diagrams that look
like they might be from around the '90 generation. If you post a valid
e-mail address, I'll send them to you (or set up an FTP where you can
download them).

 

Scratch that, '89 was the last year for the hatch.

Scratch that too, these diagrams include wiring for the hatchback and
thus must be for 89 or earlier.

 

Likely, water in the taillight.
My 85 Accord used to do it after it rained, now it does it all the time.
Wait till the gas filler neck rusts where it meets the tank, then you can
only run 3/4 of a tank of gas.

 

Pretty sure that 87 and older accords (2nd and 3rd gen) had recalls on the
fuel filler neck....Preludes too from similar years.

 

I would also guess that it's the actual circuit that detects a blown bulb,
rather than an actual bulb that's blown (anyway, you already checked the
bulbs...)

In addition to Randolph's comments below, you might specifically check the
multi-point connector that plugs into the detector modules. On my 91, some
of the contacts had corroded, which caused the problem. The modules are
located on the tail light lens assemblies - I can't remember if the modules
are visible from inside the trunk if you only remove the access panels (to
get at the light bulbs)...if not, you need to remove part of the trunk
liner. Once you have access, you'll see the modules. They're secured to the
back side of the lens assemblies, their case is either black or light brown
plastic (if memory serves correctly).

Good luck!
-Arthur