PFF - Pennock's Fiero Forum, PDA Edition

Looking for guidance on fixing horn (Page 1/1)

ElectricBoogalooBlue

JUN 16, 07:08 PM

So I bought my 87 fiero about a year ago now and have had my fair share of issues most of them revolving around my, and most others, least favorite subject, electrical. Most of them I’ve been able to figure out and I think I know the issue here but I would love a second opinion.

Recently my horn(s) stopped work on my fiero. I say horn(s) because for all I know one of them could’ve been out since I bought the car. The General Electrical situation is as follows.

1.) Checked to make sure both horns were plugged in and they were

2.) Checked to see if the relay clicked when the buttons were pressed and it didn’t so initially I impulse bought a new relay which didn’t fix the issue as the new one also doesn’t click when buttons are pressed.

3.) checked to make sure the buttons on the wheel actually worked with a multimeter. I was hoping they wouldn’t work because that’d be the simple fix but alas they worked just fine.

4.) I stuck the prong of the multimeter into the sockets for the horn relay and I was getting voltage over the prongs that initiate the relay but it seemed like it was to low to actually trigger the relay to click.

5.) I checked to make sure no power was making it to the port side horn and it didn’t seem to be getting anything but I’m not too confident in my methods

So my understanding of this is that the issue lies between the relay and the horn buttons, maybe something to do with the steering wheels connections. But I was talking to my dad about this and he seemed to think somehow it could be that the horns themselves were actually busted and has been telling me to just buy new ones. Not being one to just throw money at something I went to check and they seem like they don’t work but to be honest my method of attaching bare copper wire to the battery and touching different spots on the horn with the two ends isn’t exactly the most scientific way of checking. (And if you’re wondering yes I shocked the **** out of myself) I’m working on getting some alligator clips and sanding down the connections on the horns to be sure but my understanding is that whether or not the horns themselves work, the relay should click either way.

All I’m asking for is a green light to go on my crusade to the electronics Beyond the steering wheel and maybe some divine guidance to take on my holy journey!

In all honesty thank you for any help you can send my way I ain’t got a clue what I’m doing!

daved

JUN 16, 08:14 PM

Unplug horn relay. With meter on Ohms, check terminal B (black wire only) to ground... should read near to zero when horn button pressed.
If not, look to your horn button, or slip ring.
With meter on Volts, check terminal A (orange wire)... should read battery voltage around 12.8 Volts.
If not, look at your fuse label as 'BATT'.
This should give you a clue as to where the problem may be.

theogre

JUN 17, 10:34 AM

Unplug both horns. Run a long rather heavy "12V" wire from battery to test each unit.
One or both can be bad and kill the system and fry the relay contacts.
Because if shorted will make a big amp draw. Will often make a spark anyway to test them.

See my Cave, Horn & Defect & Connection notes shows back view of "Convenience Center" w/ horn relay

So front is

code:

C-Grn B-Blk
   A-Org
   HORN

Letters from FSM and other "books."

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 06-17-2022).]

Dennis LaGrua

JUN 17, 10:48 AM

I've had to replace the horns on two Fieros. My theory is that the horns being upfront behind the facia are exposed to the rain and a bad weather environment. If you want to determine if its the horn or relay clip a +lead of a multimeter or test light on the power lead to the horn and the other lead to ground. Have an assistant press the horn button. If you have power there its not the horn but the relay or the horn switch. In my case its always been worn out horns.
IMO, one horn doesn't give enough of a warning signal. I installed two Fiamm highway blaster horns, they are compact and plenty loud.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

ElectricBoogalooBlue

JUN 18, 07:35 PM

quote

Originally posted by daved:

Unplug horn relay. With meter on Ohms, check terminal B (black wire only) to ground... should read near to zero when horn button pressed.
If not, look to your horn button, or slip ring.
With meter on Volts, check terminal A (orange wire)... should read battery voltage around 12.8 Volts.
If not, look at your fuse label as 'BATT'.
This should give you a clue as to where the problem may be.

Ok so I tried both of those and I’m pretty sure I did both of them wrong. For the first one I plugged the positive prong into terminal B and grounded attempted to ground it…which I believe is where I went wrong. When I pressed the button the needs on the multimeter didn’t move at all even when on the lowest setting. Long and short I need a little help knowing how to ground the negative multimeter prong.
As for the second suggestion I plugged the positive prong into terminal A and assumed I was supposed to ground the negative prong which I tried and once again didn’t get any reading.

Long short I need help understanding how to ground the multimeter. I know this is pretty simple but In my defense I’m trying to teach myself most of this stuff. And Thank you for the response!

Dennis LaGrua

JUN 20, 08:54 PM

quote

Originally posted by ElectricBoogalooBlue:

Ok so I tried both of those and I’m pretty sure I did both of them wrong. For the first one I plugged the positive prong into terminal B and grounded attempted to ground it…which I believe is where I went wrong. When I pressed the button the needs on the multimeter didn’t move at all even when on the lowest setting. Long and short I need a little help knowing how to ground the negative multimeter prong.
As for the second suggestion I plugged the positive prong into terminal A and assumed I was supposed to ground the negative prong which I tried and once again didn’t get any reading.

Long short I need help understanding how to ground the multimeter. I know this is pretty simple but In my defense I’m trying to teach myself most of this stuff. And Thank you for the response!

When you use a multimeter (set to the 20VDC scale) , the - (minus) lead goes to ground that is any part of the metal on the engine block or on the frame and the + (positve) red lead is used to measure the voltage for the test.