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Old 04-07-2009, 12:00 PM   #1
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HELP! How do I test the two-tone horn RELAY?

Dear enthusiasts,

I've been having horn problems and am using the process of elimination to find the culprit. Thus far, I've replaced the air-bag retaining frame. I also found and replaced a blown fuse. Before I spend time removing the bumper and changing both the horns, I'd like to rule out the relay. I was told that if I do not hear "clicks" when I press on the airbag, then it is the relay problem. However, I did not press on the airbag when I opened up the steering and I've returned the tools. Therefore, is there any other way to test the relay? I understand that the location of the relay is under the front dash. Can I simply pull another one out and swap it with the horn relay? Or is there another way to hear the clicking sound besides pressing on the airbag?

Please advise and thanks in advance.

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Old 04-07-2009, 12:47 PM   #2
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I could hear my relay clicking as I pushed / pulled out the air bag. (I have bad horns, so no Beep Beep as I did this).

Hook up a meter to your horn wires (if you front bumper is still off) and watch if power gets to the horns.
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Old 04-07-2009, 03:29 PM   #3
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Listening for a click doesn't necessarily indicate a relay is OK, some relays are solid state and so do not click at all.

To do a proper test, you really need a DMM (digital multi-meter), 2 small jumper wires and at least a 9-volt battery, or you can use the car battery (12V). Remove relay before testing.

First, using the DMM set to ohms, check resistance test between terminals 85 and 86. Resistance value (ohms) should be 75 15 ohms for resistor equipped relays.

Next, connect the DMM between terminals number 87A and 30. Continuity should be present at this time - meter will read 0.

Now, connect the meter between terminals number 87 and 30. Continuity should not be present at this time - meter will read infinity (sign).

Now use a set of jumper wires (16 gauge or smaller). Connect one jumper wire between terminal number 85 (on the relay) to the ground side (-) of a 9-12 Volt power source - the battery or 9-volt, and attach the other jumper wire to the positive side (+) of the same power source. Do not connect this jumper wire to relay at this time.

CAUTION: Do not allow the DMM to contact terminals 85 or 86 during these tests while it is in the resistance (Ohms) mode - you'll damage it.

Then, attach the other jumper wire (9-12V +) to terminal number 86. This will activate the relay. Continuity should now be present between terminals number 87 and 30 - (meter reads 0). Continuity should not be present between terminals number 87A and 30 - (meter reads infinity).

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Last edited by Lil bastard; 04-07-2009 at 03:34 PM.
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