no luck on tech forum so, i thought i would give this forum a try.

i'm trying to test my horn relay to see if it has malfunctioned. do i test for voltage, continuity????


thank you

 

i really don;t think your relay went bad. it could but the failer rate is so low. press your horn button and listen for the relay click. if you hear it get a test light and test it at the horn wire if you don;t hear it click test it at the relay conection

 

grab a multi-meter that can test ohms. Stick the probes on both sides of the Coil (typically pins 85 and 86). It should read around 50 ohms give or take. The contacts on the switching part shouldn't go bad, so if the coil is good I'd check the line as someone said above to make sure it's got +12 when the horn button is pressed. Or you can do these steps vice versa of course

 

Whoa!!! The resistance of the coil can read almost anything depending on the type of relay. I just grabbed one off the shelf and the coil read 75ohms. There will be resistance but the only safe thing to say about it is that it wont b a single digit number. The contacts are what go bad. Just before the contacts fully close there is a brief (milliseconds) arc. This wears out a relay. Also, all metel corrodes. Even if the relay is not used very much, it may be bad. Get the help of a buddy to push the horn button while you check for 12v at the horn.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realblag &raquo;</TD></TR><TR><TD CLASS="quote">Whoa!!! The resistance of the coil can read almost anything depending on the type of relay. I just grabbed one off the shelf and the coil read 75ohms. There will be resistance but the only safe thing to say about it is that it wont b a single digit number. The contacts are what go bad. Just before the contacts fully close there is a brief (milliseconds) arc. This wears out a relay. Also, all metel corrodes. Even if the relay is not used very much, it may be bad. Get the help of a buddy to push the horn button while you check for 12v at the horn.</TD></TR></TABLE>

Well put

I go through a lot of relays because in the old school days, I used to do a lot of ambers for the street racers. Ofcourse, using these BOSCH relays for turn signals will put them through hell and sometimes go out in as fast as 6 months with quick blinks.

BTW, the horn trigger is usually Negative (-). So put the clamp of your test light on the battery.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realblag &raquo;</TD></TR><TR><TD CLASS="quote"> Just before the contacts fully close there is a brief (milliseconds) arc. This wears out a relay. Also, all metel corrodes. </TD></TR></TABLE>

This is called "Pitting" we see it mostly on light flash relays.

do you have +12 and ground on the 85 and 86 when the horn button is pressed ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nOOber &raquo;</TD></TR><TR><TD CLASS="quote">

This is called "Pitting" we see it mostly on light flash relays.

do you have +12 and ground on the 85 and 86 when the horn button is pressed ?
</TD></TR></TABLE>

i haven't tested the relay yet, but, should i have 12 volts between those two terminals?

will this be the correct procedure to test if the horn is getting 12 volts?: unplug the harness on the horn and put the positive and negative probes on each terminal to see if it is receiving 12 volts when someone pushes the horn?

 

so, if i understand this correctly, i should either have 50+ ohms between terminals 85 and 86 or 12volts? and i have anything that is 50+ ohms, the relay is in good working order?