Re: "up shift" indicator out on 85' 4ksq

[BJohn77777@aol.com]

Will,

In a message dated 96-05-09 19:58:59 EDT, you write:

>Three months ago, i purchased a 4ksq with 129K miles, the "up shift" 
>indicator just recently went out, but was working. The original owner 
>thought i may have problems with the engine now, since that indicator is 
>part of a govenor for the fuel injection and or engine...according to him.
>I thought it may just be the bulb?, Engine's running fine.........I'm new 
>to Audis, but learning quick; any help would be appreicated
>
>
>Will
>Auburn, CA


The circuit in question is very simple:

 1. A vacuum switch in the distributor vacuum advance line, (has wires that
connect to #2);
 2. A electronic circuit(Upshift control unit=relay #3 in the main relay box)
to compare vacuum and ~2000rpm (from      OXS control unit, {the main
computer}) to activate #3;
 3. A light emitting diode (LED), {upshift indicator arrow};
 4. Associated wires, connectors, and vacuum lines.

Find the vacuum switch ~ 6"-10" from the distributor vacuum advance.
Carefully disconnect the wires and jumper the plug.  Start the car and run up
to ~2k to 2.5k rpm.  Light should come on.  If it does, suspect one of the
vacuum circuit items.  I found mine was caused by the distributor vacuum
advance diaphram leaking big time, allowing zero vacuum to the switch along
with no vacuum advance at dist.  If it does not come on, any of the other
items may be at fault.  Easy to $ub relay, computers are $$$, and LED's
rarely burn out.

If you have any questions or need info to walk you thru troubleshooting just
e-mail me.  I'll get "Mr. Bentley" out and guide you through the mess. Good
luck.

Bruce Johnson
85 4Kcsq
Olympia, WA