Date: Tue, 15 Jun 1999 08:07:45 -0600
Reply-To: Wendell Hovey <whovey@SILVER.SDSMT.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Wendell Hovey <whovey@SILVER.SDSMT.EDU>
Organization: South Dakota School of Mines and Technology
Subject: Re: HOWTO: Audiovox cruise control install experience
Content-Type: text/plain; charset=us-ascii
The system uses two pickups and compares the signals. If the signals stay in
sync, the sustem knows the engine to wheel connection is not broken - ie that
the clutch is not disengaged. If the signals get out of sync, the system knows
that the clutch has been disengaged and that the engine is beginning to
over-rev. It then disengages the speed control device.
Wendell
"Michael A. Radtke" wrote:
> Eric,
>
> Thanks for the detailed HOWTO.
>
> I installed a similar unit a while back and it seems to work fine on my '84.
>
> 1) Why did you use the magnetic pickup? I thought that was only
> necessary with an automatic transmission? My installation senses
> engine speed through the coil wire.
>
> 2) A disengage down hill is a safety feature. The idea is that the
> car shouldn't continue to speed along, or increase speed over some
> length of time with that the cruise thinks is a closed throttle. I
> haven't experienced it with my current cruise control, but I did
> experience it with the previous one on long mountain descents.
>
> 3) Just a week ago, I made a wiring change in my installation to
> reflect behavior that I was used to in all my previous cruise
> control installations. The AudiVox unit acts like most factory
> installations in that there is no provision to disengage the cruise
> without losing its setting except by using the brakes. All of my
> aftermarket units, until the AudioVox, retained the last setting
> when switched off and then back on again. Only using the set key,
> or turning off the ignition unset the unit.
>
> I measured the current draw of the unit and found it to be less
> than 100 milliamps when disengaged, so I reasoned that I could
> leave the unit active all the time. So I made the following wiring
> modifications.
>
> a) I connected the power to the unit from the control, and
> connected directly to the fused power source. This leaves the
> unit powered on any time the ignition is on.
>
> b) I disconnected the wire from the unit that senses brake light
> battery voltage and connected it to the switched power source
> from the control unit. This is the place the cruise unit
> power lead was originally connected. This change supplies the
> cruise with brake light reference voltage only when the cruise
> switch and the ignition switch is on.
>
> c) I added a diode in the wire from the brake lights to the cruise
> unit. I don't know whether this was necessary, but with the
> ignition or cruise switch off, stepping on the brake pedal
> causes this lead to go to 12 volts. With my other
> modifications, the brake light reference voltage is zero and bad
> things could happen to the cruise. The diode blocks reverse
> current flow.
>
> I determined that the current flow was out of the control unit,
> so the arrow on the diode should point toward the brake lights
> and away from the cruise unit.
>
> With the above modification the cruise acts the same as before, but
> will return to its last speed setting if the unit is on and resume
> is pressed. It does lose its setting on ignition off.
>
> Thanks again for sharing.
>
> Mike '84 GL '58 Isetta (no cruise)
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