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914World.com _ 914World Garage _ Yeah - another horn issue - 1973 914

Posted by: dhempy Jun 28 2020, 04:55 PM

Hello everyone,

I need some help tracking down a horn issue on my '73 914.
I have had the car 20 years and can't remember the last time the horns worked.
I decided to try to fix the horns before I installed a new JWest fuse box.

Troubleshooting procedure

1. Orig horns did not work with 12v - bought new Hella Sharptone Hi/Lo twin horn kit
2. Installed new horns, ran a jumper from pin #30 (relay out) to pin #87 and the horns work. (And they sound great too). Does not work with the horn button yet (Ign on)
3. Ordered a couple new relays (just in case). I manually checked the old one(s) with a 12v small backup battery from my garage door opener connected to pins #85 & #86 on the relay - it clicks then i checked continuity at pins #30 & #87 - all good. Relays work but the horn still does not work (and no clicking at the relay)
4. Here is where I am stuck - pin #86 should have 12v (Ign on) and does not. I have continuity between #86 and fuse #8 but I do not have 12v at fuse 8 with the ignition on. Swapped fuse and checked continuity too on new fuse just to be certain.

How is 12v fed to fuse #8?
What should I do next? Am I missing something?

I want to get this resolved before I throw another variable into the mix by installing the JWest fuse box. All comments about this replacement fuse box are welcome

At least the horns look cool installed

Posted by: 914e Jun 28 2020, 05:05 PM

I think fuse 8 is fed by fresh air relay.
That fuse powers the coil of the horn relay.

Posted by: dhempy Jun 29 2020, 07:54 AM

Thanks 914e!.
I'll check that later today.

Posted by: dhempy Jul 2 2020, 03:24 PM

Yeah it was the fresh air relay. It clicked but the points were burnt.

Thanks 914e!

Posted by: brant Jul 2 2020, 03:32 PM

QUOTE(dhempy @ Jul 2 2020, 03:24 PM)

Yeah it was the fresh air relay. It clicked but the points were burnt.

Thanks 914e!

dave

where is that fresh air relay located?
On the back of the fuse board... or under the fresh air motor?
I need to check mine today

does anyone have instructions about which relay on the back of the fuse panel is for which item?

brant

Posted by: 914e Jul 2 2020, 05:08 PM

Relay locations at the fuse box

https://bowlsby.net/914/Classic/zTN_Elect_Relays_MainFusepanel.jpg

Posted by: brant Jul 2 2020, 08:53 PM

Thank you!