[V6-12v] '94 100 - No AC, sunroof, windows, fan, turn signals

[Tom Christiansen]

Kent,

I glanced over the schematics for my 1994 90 S. I suspect yours is 
wired in a similar way. The wiring diagrams are not exactly easy to 
read as all wires seem to go everywhere, but here's what I gather:

The load reduction relay is turned on for normal operation. When the 
load needs to be reduced, the relay is turned off.

I somehow got the impression that the load reduction relay would be 
turned off when the engine was about to overheat, but I must have 
dreamt that or something. The only thing I can find that controls the 
load reduction relay is the ignition switch. The relay makes sure 
that all the unnecessary items are turned off when you start the car 
or when you turn the key from the run position to the stop position.

The load reduction relay controls:
* Turn signals
* Fog lights
* Windshield wipers
* Rear window defroster
* Power windows
* Seat belt warning relay
* Radiator fan, high speed relay
* HVAC fan
And probably a whole bunch of other stuff that I haven't found. If 
you have the schematics, the wire at the top marked X is the switched 
12V from the load reduction relay.

In my car, the load reduction relay is supposed to sit in position 5 
in the relay panel (according to the schematic anyway). I believe 
that's out front in the fuse box. I doubt cleaning the contacts is 
possible. You can probably pry the relay open and get at the contacts 
with a nail file or something, but I doubt that's a good permanent 
fix. Just spend the $20 (I'd think) on a new relay.

One interesting thing, though:
The horn is driven by the same connection on the ignition switch as 
the load reduction relay. So if you lose all the functionality 
mentioned above, try honking the horn. If the horn doesn't sound, 
it's a bad ignition switch. If the horn does sound, it's a bad load 
reduction relay. At least that's what I can get from reading the 
schematics for my car. YMMV.

Tom

At 07:22 AM 8/20/2005, Kent McLean wrote:
>A few days ago, I started my '94 100 S Avant and I didn't have AC,
>sunroof, windows, HVAC fan, or turn signals.  I killed the engine,
>restarted, and everything worked as normal.
>
>Yesterday, same thing, except I didn't realized it until I was on
>the road (at the beginning of a 75 mile commute) and couldn't kill
>the engine.
>
>Searching the archives, I suspect the problem is the "load reduction
>relay".
>
>Questions:
>
>- Where is it (location, labeling) on the C4 body?
>- Can I open it up and clean it, or is a new one in order?
>
>Dank im voraus,
>--
>Kent McLean
>'94 100 S Avant, "Moody"
>'89 200 TQ, "Bad Puppy" up in smoke
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