No working horn - or just the next thing that doesn't work!

Post by **scot850** » 13 Dec 2017, 16:05

Ok, firstly I have had the steering wheel of and had it in bits to replace the airbag bolts. However, never checked if it worked before that so maybe it never worked since I got this 'new' PITA Volvo V70.

I plan to pull the horns and check they work and the connectors are good.

At the steering wheel end how do I test for continuity from the horn ring to the wiring harness?

Does pressing the horn ring just act like a switch and close a circuit? If so how does that work as I thought the only contact point was the one contact on the rear of the wheel to the clock-spring. I have a couple of spare used clock-springs if needed, but what am I checking for and where to eliminate the steering wheel from the equation?

I have watched Roberts Video but still not clear on the working process other than fit the airbag with the RH bolt first. No idea why that would be a thing, but did that anyway.

Thanks,

Neil.

Post by **abscate** » 13 Dec 2017, 19:50

Most horns work by having 12V at the horns switched through the ignition, then the horn button on the steering wheel grounds the other side of the horn to sound it.

If you've got the steering wheel off, quick test is to find the ground wire and with ignition on, touch it ground....BRAP!!

If that doesn't work, get your voltmeter and, ignition on, look for 12V on the violet wires , terminal 2 at horns. If not present, follow the wiring diagrams up to find the voltage at the terminal connector, then the relay, then the fuse.

Hers the 99 diagram, I'm guessing 00 is the same

Post by **scot850** » 13 Dec 2017, 22:13

Thanks for the wiring diagram info. I decided to do the checks tomorrow in daylight but as I had a little time tonight I thought it might be worth remove the 2 horn units and clean the contacts with electrical cleaner ready for testing.

I was surprised to find both horns were disconnected at the connector. Not sure why that should be, but if for once I get lucky I could only hope it is a simple as that, but then the question would be, why were they disconnected in the first place?

I give up trying to figure out what the previous owner was on......

Neil.

Post by **abscate** » 14 Dec 2017, 00:32

They were just pre-staging the 12V check at the connector for you.

I hope you don't answer your question when you reconnect them, and turn the ignition on, and wake up the house. If that House , the fault is just up at the steering wheel ground.

My guess is just another piece of POD...previous owner dreck.

LOB · Post by **LOB** » 14 Dec 2017, 04:54

The same reason I disconnected my horns for a while. The horn is constantly grounded at the steering wheel and hence they make noise constantly. Open the pad on the steering wheel and fix the connection! Be careful with the airbag. Read and learn prior to this operation. Do not disconnect the airbag!

Post by **scot850** » 14 Dec 2017, 08:21

Thanks guys. Warnings noted!

I have had many steering wheels off these cars and airbag removals. I take care when doing so and leave the battery disconnected for a long time prior to removing airbags. Having the battery connected when playing with the airbag connectors is just plain stupid.

I know the ground looked ok, but until I find why the horns were not connected, I will just have to wait to find out!

Neil.

Post by **abscate** » 14 Dec 2017, 09:14

You could test it quietly by looking for continuity between the ground terminal (VIOLET WHITE) wire on the horn or connector and a good ground on the engine. There should be INF resistance (open circuit) until you push the horn button

Post by **scot850** » 14 Dec 2017, 11:01

That is a great idea! That's the simple test type I like!

Neil.

Post by **scot850** » 15 Dec 2017, 15:11

Clearly I am no electrical whizz, but I thought I followed your simple instruction correctly abscate?! Clearly not as I got nothing when trying continuity for the horn.

With both horns removed, I had the negative probe connected to the engine earth. Had the positive connected to one pin on the 2 pin connector for the LH horn. Had my son press the horn and the reading stayed at -1 on the meter. Tried it again at position #I and #II and the same. Unusual for Volvo the connector and horn had no numbering to identify which wire is which and they are both covered in electrical tape so I could not see which wire is which. Tried the other pin and exactly the same result. Finally tried the other horn (RH) and exactly the same. So clearly I have done something wrong. Should I have just shorted the 2 pins in the connector out to check this as one pin goes to ground anyway?

Thought, 'What the heck', and plugged one horn in (RH) and had my son press the horn and it worked fine. Connected the LH horn and both worked when the horn was pressed. So both the horns are working, and so far no continuous horn blaring due to a internal short in the steering wheel. Now just have to take the car for a run and see if I get any random horn blasts.

Until I do that run, I am trying to figure out why the connectors were removed, but maybe there was a problem that I 'accidentally' fixed when working on the steering wheel? Who knows??!

Neil.