'93 Accord Cruise Control ECU; which years?

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scube - 22 Mar 2006 04:03 GMT

My Honda Accord is a 1993 with manual transmission. I have a problem
with my cruise control and have narrowed the issue down to the ECU. I
have a question here...

I was wondering what years and model Honda vehicles can I use the
cruise control ECU from to put into my Accord?

Thanks for any advice/information!!

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jim beam - 22 Mar 2006 05:15 GMT

> My Honda Accord is a 1993 with manual transmission. I have a problem
> with my cruise control and have narrowed the issue down to the ECU. I
[quoted text clipped - 4 lines]
>
> Thanks for any advice/information!!

ok, so for the benefit of the group, talk us through your diagnosis and
how you concluded it was the ecu.

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scube - 23 Mar 2006 03:33 GMT

Hmmm,
well, first off the cruise control ECU (in a LHD car -left hand
drive) is to the left of the steering column blocking the main relay.

As far as my troubleshooting goes, I guess I'm not yet there after
all, at least not 100%. I browsed around the internet for a
replacement cruise control ECU and the one's I found were "good" for
1990-1993 models. Going on this information I used my 1991 Accord
manual for the cruise control diagnostics and followed the steps.
There is a table for each wire going into the control unit and I
checked them all for either voltage or continuity to GND and almost
everything checks out. However, I found some interesting things that
I'm having a hard time explaining. If anyone can help that would be
great.
I have the cruise control diagnostics for a 1990-1991 and a 1994
Accord. The only differences between the '91 and the '94 are 1) an
extra wire is used on the '91 model which supplies voltage to the ECU
when the engine is running, and 2) the '91 model has continuity to GND
when the clutch is PRESSED and the '94 model has continuity when the
clutch is NOT PRESSED.

My '93 however has a hole in the clutch where the push-button clutch
switch goes right through. It makes no sense that this hole is there,
so I'm guessing there was a stopper of sorts that must have fallen out.
I plugged it with a screw and when released (NOT PRESSED) I get
continuity, which is against what the '91 diagnostics say I should be
reading.
I must be mistaken that other model Accords have the same ECU, but I
don't know which to go on as I am missing my '93 manual. I tried both
states and neither fixed my cruise control problem. I checked the
diaphram on the actuator and the solenoid relays and they all check out
operational.
Also, for an Automatic car, this clutch wire is used for the same
purpose (can't engage cruise when not in the proper gear: 2, D3, D2).
So, I'm curious, as there is no difference in the troubleshooting, if
an Automatic ECU can be swapped for a Manual ECU.

Can anyone verify the output of the clutch switch when it is PRESSED
and NOT PRESSED for a 1993 Accord? I don't see another switch on the
clutch, so I'm curious if this switch also performs the start-check
which does not allow the car to start unless the clutch is in. Any
help or suggestions is greatly appreciated.

Thanks!

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Michael Pardee - 23 Mar 2006 04:09 GMT

> Hmmm,
> well, first off the cruise control ECU (in a LHD car -left hand
[quoted text clipped - 40 lines]
>
> Thanks!

According to the Helm manual for the '93 Accord, the switch is closed (pins
B-C) when the pedal is up and is open when the pedal is depressed. The
switch for the cruise control is the upper switch, the one mounted
horizontally. The lower, angled switch is for the starter interlock.
(According to the picture.)

Look around under the mat or carpet for the plug. My Nissan had one of those
for the brake lights that fell out. It looked like a phenolic mushroom. If
it is missing I'm sure the cruise control won't engage.

Mike

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scube - 24 Mar 2006 14:52 GMT

Hmm,
well lower angled switch in my car does nothing to the starter
interlock, meaning I can toggle it w/ not change in if my car starts w/
clutch pressed or not. The wires coming from the horizontal switch do
not go to the cruise control either. However, the ones coming from
the angled switch do goto the cruise control.
I looked at the diagram for the '91 and it is hard to distinguish
which switch the arrow is actually pointing to. Another note is that
this '91 manual says that pins A-B are open when pedal is pushed
(push-button is out) and closed when released (push-button is in).
There is no mention of pin C, though it is a three position connector,
so maybe the manuals refer differently to the pins in question. This
is how the pinout is for the '91 Accord (lock tab is facing up)
__||__

|x B A|

~~~~~~
With the far left terminal not in use. I'm still confused as to
which switch it is, but deduction tells me it is the lower angled one.
Any light someone could offer would be appreciated. Thanks for your
input Michael!!

I think I've found a problem w/ an intermittent brake switch. I
pulled it out and it worked, but when I put it back in it would work
frequently (no problem w/ my brake lights though...??). I'm hoping
that when I fix these two things my problems will go away, but I rigged
them up to work and it still didn't.

Does anyone see a problem w/ using an Automatic cruise control unit
on a manual? As I stated above the diagnostics are indifferent to
which style it is, I'm just curious if there is some different
operation from the Control Unit which would be impacted by the type of
transmission in the car. It all seems straight forward: The wheel
rotation is reported to the vehicle's cruise control unit and the
control unit adjusts the actuator to keep that speed constant. Am I
missing something?

Thanks all...

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Bob - 22 Mar 2006 05:21 GMT

>My Honda Accord is a 1993 with manual transmission. I have a problem
>with my cruise control and have narrowed the issue down to the ECU. I
[quoted text clipped - 4 lines]
>
>Thanks for any advice/information!!

For my knowledge, where is the ECU?

Thanks

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Elle - 23 Mar 2006 17:05 GMT

You can compare part numbers for different models and years
using www.hondaautomotiveparts.com or www.slhonda.com .

I am a little confused about your wording here. There's the
ECU, short for "Engine Control Unit" or similar that's
generally located in the passenger side footwell. Short of a
flood saturating the inside of the car, these rarely fail.

Do you instead mean the "cruise control actuator"? You'll
see a drawing of this under "Auto Cruise" at the sites
above.

> My Honda Accord is a 1993 with manual transmission. I
> have a problem
[quoted text clipped - 7 lines]
>
> Thanks for any advice/information!!

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Elle - 23 Mar 2006 17:41 GMT

Oops. Helps if one reads the whole thread (plus the server
seems a little whacked and is posting messages out of
synch).

My Chilton's manual calls what scube describes the "cruise
control module" and the "cruise control unit." They appear
to be the same thing. I am having trouble locating it at
www.hondaautomotiveparts.com for a manual transmission. The
"Fuse box-Relay" section seems like the best bet.

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scube - 25 Mar 2006 02:04 GMT

Ahh, yes! I finally got the cruise control to engage and actually
affect the velocity of my car!! My results:

First, the brake switch is faulty. I pulled it apart and fiddled
with the solder connects. It works now, but I don't know for how long.
Second, my adventures with my clutch pedal also had an effect on the
operation. My "pedal pushed" switch was not engaging.... The cruise
control thought my clutch pedal was always depressed. The pedal was
missing a stopper and so I plugged the hole w/ a screw.

From my findings, in my 1993 Accord, the lower angled clutch switch
is for the cruise control. That was good because it would be a
mission to get to the other switch!!

Thanks to you all for your input and questions, this dog will finally
hunt again!!

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Michael Pardee - 25 Mar 2006 13:32 GMT

Thanks for the feedback, and congratulations on the triumph!

Mike

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Graham W - 25 Mar 2006 15:32 GMT

> Thanks for the feedback, and congratulations on the triumph!

Seconded!

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scube - 26 Mar 2006 01:41 GMT

Thanks for the encouragement guys. Thanks goes out to all the helping
friendly users of this NG. I'm glad to have my cruise control back!!

... join me next week in the adventures of diagnosing my ABS issues...

scube

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