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horn question/update

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

This topic is in the MVS Volvo Repair Database » How To Fix A volvo 850's Horn
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misha
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Volvo Repair Database horn question/update

Post by misha »

Hi guys!
I need to replace my horns.

So...i have another Mixo horns,but they are from VW Audi and don't have one connector with 2 pins inside like oem Volvo.It have 2 separate connections and i don't know which one is + and which one is -(if that actually matters).

Any help would be appreciated! :wink:
Last edited by misha on 31 Jul 2010, 18:27, edited 1 time in total.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

Ozark Lee
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Post by Ozark Lee »

It may or may not matter, use an Ohmmeter to check each pin on the connector to the frame of the horn. If one shows very low resistance then that would be the negative terminal. If both show high resistance then it doesn't really matter.

...Lee
'94 850 N/A 5 speed
'96 Platinum Edition Turbo
Previous:
1999 V70XC - Nautic Blue - Totaled while parked.
1999 V70XC - RIP - Wrecked Parts Car.
1998 S70 T5
1996 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

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misha
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Post by misha »

Ok,i solved the problem with my horns.

Before you decide to replace your horns,here is what you need to do:
-first....every Mixo horn have one torx screw for adjusting.That screw is covered with a plactic cap and under it there is a silicone covered torx screw.Peel off the silicone with a knife or something in order to access that screw.
-connect the horn to a 12v battery charger and start with turning that torx screw from left to the right untill the horn activates,but do that very,very slowly.
-when horn sounds,disconnect it from the charger and try again
-if the horn works perfectly you can put it back on the car
-sometimes there is a need for fine adjusting moving the screw to the one side for 1mm

****12v battery charger have much less amp power than the battery,so the horn will perform very weak sound****

-but....once it sounds you can connect it directly to the battery and try it out
-if moving that torx screw isn't helping you need to replace the horns.

I managed to save the "high" one,but the "low" one was toast.So,i adjusted the "high" one and it works perfectly,but for the "low" one i needed to splice the connector from the car because it is from VW Audi and have 2 separate connections instead of one connector like the stock one.

Mission completed!

About polarity.....(only for Mixo horns that have 2 separate connections)

There is + & - on the connector itself,but on the horn it says just 12v.There is no difference in sound if you connect it one way or another.I think that is just like on thermoswitches on older cars(it have + & -,but it doesn't matter how you will connect it to the car).

Misha.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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jreed
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Post by jreed »

Thanks Misha!
I had a non-operational low horn (Mixo TR99, Volvo part 9169551) that I fixed by removing the cap and adjusting the Torx 20 screw.
Horn after removal from car.  Cap is covering the torx 20 screw.
Horn after removal from car. Cap is covering the torx 20 screw.
Horn1.jpg (102.15 KiB) Viewed 3083 times
After you lift off the cap, the screw can be adjusted with a T-20 driver. I needed to turn mine about 1/3 of a turn counter-clockwise to get it working again. I took the precaution of marking the original setting of the Torx bolt with a little black marker so I could keep track of where I started out.
Adjusting the T-20 screw until the horn works again.
Adjusting the T-20 screw until the horn works again.
Horn2.jpg (125.23 KiB) Viewed 3083 times
After it was working, I reinstalled the black plastic cap and put silicone sealant inside and over the cap to keep out water.
Cap reinstalled and covered with silicone RTV sealant to keep out the elements.
Cap reinstalled and covered with silicone RTV sealant to keep out the elements.
Horn3.jpg (96.23 KiB) Viewed 3083 times
I reinstalled the horn using a little blue Loctite (there was red Loctite on the bolt originally). It's working well now!
:)
1997 855 GLT (Light Pressure Turbo) still going strong. Previous: 1986 240 GL rusted out in '06, 1985 Saab 900T rusted out in '95, 1975 Saab 99 rusted out in '95, 1973 Saab 99 rusted out in '94

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misha
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Post by misha »

I'm glad that i could help! :wink:
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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