On Wed, 15 Jul 1998, Frank Kucharik wrote:
> Neither worked when I bought it. I just installed 2 new horns,
> but the wiring/switch must be bad. I have an extra switch,
> and can see how the horn is wired in the diagram. The question
> is, where is the horn relay/what does it look like? I assume
> I can just run new wires from switch->relay->horn->horn, with
> all the proper grounds? How can I tell if the relay is bad?
A horn relay is a sub-switch. The power required by the horns is quite a
bit, so the actual electricity to them is turned on and off by the relay.
You turn the relay on and off with the horn button.
Relays are about half the size of a film canister (give or take), and will
have 4 or 5 spade terminals on the back. (hopefully yours is plugged in).
You can tell when they're working if you can hear a 'click'. (if you
can't hear it, put your hand on the top of the relay housing and push the
horn button (might need a helper)), you should feel a click.
If no clicks happen, pull out the relay (there might be some sort of
restraint holding it in) and replace it with a new one.
There should also be fuses in the wires that lead to the horns. If they
are blown, there might be a good reason for it-- frayed wire, blown horn,
bad relay.
> Now the wipers - no clue where the problem might be. The wires
> were disconnected - I connected them according the the wiring
> diagram, no luck. Any suggestions on how to diagnose what
> is wrong (i.e. with a voltmeter?) Is there a way to ensure the wires
> are working up to the wiper motors?
The wipers have 3 wires (at least- more for a 2-speed wiper!). One is
ground (this can also be acheived through the housing of the motor). One
is constant power. This is so the wipers will park when you turn off the
switch (it keeps the motor turning until they're parked, when a button
breaks the circuit and stops the wiper arms). And the rest are supplied
via the switch-- 'on' for one-speed wipers, 'slow & fast' for two-speed.
You need to figure out which wires are supposed to have power and test
that they really do. Use either a light-up circuit tester, or a
multimeter. With a light-up tester, clip the alligator clip to ground
(brake line, engine block, etc) and poke the other end on the wiper
terminals. It should glow for at least one. They ignition might have to
be 'on'.
(as an aside, there might be a problem with your ignition switch too,
causing no power to go to the horns/wipers)
When testing wiring I like to take the battery out and use a resistance
meter. If things that are supposed to have power are always continuous to
ground, then you have a problem. If there's never any continuity between
power at battery and power at accessory (wiper motor), even when you
fiddle with the switch, then there's certainly a wiper problem.
Remember, check it twice to make sure! There's no witchcraft in wiring
diagnosis, it's just diagnosis. You could make a list of ALL things
involved in a certain circuit (ie- battery, wires to relay, relay, wires
to horn, horn), test them individually and check each one off. If
everything checks out OK, make sure that you can follow the path of Mr.
Electron through the whole works. ;-) If he can't make it to ground,
then you will have no electricity.
-Malcolm
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