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View Full Version : Any FJ40 horn experts?


corsair23
08-06-2007, 10:48 PM
I searched MUD and found a link to a really nice write up on FJ40 horns (http://www.globalsoftware-inc.com/coolerman/fj40/8.htm) by Coolerman...

That said, before I go off on a wild goose chase I figured I'd ask you all if maybe this isn't just a simple issue.

Background...My horns worked fine on my FJ40, until I started monkeying with stuff that is :mad:

I installed my Grant Security System and new Grant steering wheel, replacing my old Grant wheel. I followed the directions to the best of my ability and things seemed to go well. Had some issues with the roll pin for the signal cancellation but I think I got that figured out.

Anyway, I get everything installed, connect the battery back up and hit the horn and all I get is a week "brrrrrrrp" or just a click/thunk noise. WTF? Recheck the directions, connections, etc. etc. and nothing. I disconnect one horn and get a nice loud BLAST. Doesn't matter which horn is connected alone (high/low tone), I get the horn, but connect both at the same time and I get squat.

Any hints on what might be a simple solution to my problem?

SteveH
08-07-2007, 12:30 PM
First, If you have a factory horn relay, remove the cover and inspect the contacts.

Otherwise, You may have a weak connection (either in the steering wheel area or elsewhere) that only allows enough current for one horn to work. Put a voltmeter on each horn as you blow the horns and see if you're simply not getting enough voltage (and ultimately current) to blow two horns at the same time. Try installing only the voltmeter in place of both horns to see what voltage the horns are seeing under no load. Then plug in one horn and measure at that horn, and at the other unplugged horn. Then plug in both and test at each horn. Test all reasonable combinations.

If you don't have a horn relay, consider adding one, using the power to operate the relay from the one horn. Run a wire to the battery, use a 30 amp relay, and you can power 4 horns from a Buick Park Avenue, if you like.

corsair23
08-07-2007, 03:12 PM
Steve,

Thanks for the help! I looked for the horn relay last night and didn't see it so it so it is possible a PO removed it somewhere along the line. I am baffled why the horns worked before and not now but I'm sure it has something to do with the Grant Security System dropping the voltage.

By chance do you know where the horn relay should normally be located?

CardinalFJ60
08-07-2007, 03:15 PM
IIRC, it's on the PS fender in the engine bay. I had a dangling connecter right there

corsair23
08-07-2007, 03:29 PM
IIRC, it's on the PS fender in the engine bay. I had a dangling connecter right there

I'll look again for it but me thinks the PPO probably removed it :rant:

Oh well, I'll be one horn for awhile...Now, do I want to have the high tone or the low tone working :hill:

Shark Bait
08-07-2007, 04:27 PM
I've got 3 sets of the newer style hi & low horns. I'm going to have to go check to see if I even have a horn relay in my project. :o

corsair23
08-07-2007, 06:28 PM
From the linked web page above and per Shawn here is where to look :)

** Update 10-1-2004 I bought a pair of inner fenders from Ron Lang in Colorado Springs. On the passenger side was a GOOD horn relay! My horns do now blow! **

Shark Bait
08-08-2007, 12:16 AM
I read all that and don't see the harness connector. Can anyone help me out with a picture of said horn relay in it's proper location? :confused:

SteveH
08-08-2007, 11:56 AM
I have never found the horn relay in my '78 FJ - but I did find one on my '76 FJ55.

If anyone finds the location, please photograph it. To try to locate it, I disconnected both horns and never heard a clicking sound from under the hood, which would help you find the relay.

Shark Bait
08-08-2007, 12:16 PM
I have never found the horn relay in my '78 FJ - but I did find one on my '76 FJ55.

If anyone finds the location, please photograph it. To try to locate it, I disconnected both horns and never heard a clicking sound from under the hood, which would help you find the relay.

Thanks Steve. I'm wondering if maybe I don't have one either. I do have 2 wires to the horn locations on each side. I also have a socket up on the firewall and I have a relay in my box of stuff that looks like it would fit. It's not marked. I thought my wiring harness was '78 FJ40 and it may be. We'll see. I can post up pics. :eek:

corsair23
08-08-2007, 02:18 PM
I read all that and don't see the harness connector. Can anyone help me out with a picture of said horn relay in it's proper location? :confused:

Found mine :D

I'll try to take a picture of it tonight. I'm not sure if it is in the stock location and somewhere along the line the factory harness/connector went bye-bye and female connectors were spliced on but it is there.

Mine is located on the top of the PS inner fender, bolted to a welded nut on the fender. Just rear of what would be the middle of the fender and it looks like this (http://www.globalsoftware-inc.com/coolerman/fj40/Page8Images/1971HornRelay.JPG) or this (http://www.sor.com/sor/cat190.tam?cart=07H08ohq.tsf&lpg=%2Fsor%2Fsearchresult%2Etam&lpt=1186600205&xax=268&page%2Ectx=cat190%2Etam) or this (http://coolfj40.stores.yahoo.net/hornrelay.html) but without any stickers/markings other than the stamped B, H, and S as seen in the first link.

From the electrical diagram posted by Coolerman (here (http://www.globalsoftware-inc.com/coolerman/fj40/Page8Images/343ElectricalWiringDiagramFJ40(L).jpg)) the two horns are spliced together and connect to the "H" on the relay, power comes from the fuse block and connects to the "B" on the relay, and then a wire runs from the horn button itself and connects to the "S" on the relay.

Mine looks a little "weathered" but I haven't had a chance to test it. I'll try to clean it up and see what happens. If that doesn't work then I may just buy a new one and be done with it. Need to call Burt and see if they carry the item or if they can get it or add it to the growing list of stuff to order from CDan.

corsair23
08-09-2007, 02:12 AM
If anyone finds the location, please photograph it.

Here are some pics from my 12/74 FJ40. Horn relay is OEM, probably original, and as far as I can tell it is sitting in the stock location (based on SORs drawing). Sits a little further back than I first remembered. I think I'm just going to see if I can find an aftermarket relay and see if my horns will start working again. I did spend about 15 mins cleaning up this one and still nothing but a weak "brrrrrrrp" :mad:

corsair23
08-09-2007, 02:13 AM
One more....

SteveH
08-09-2007, 10:20 AM
Thanks for the photos. I'm convinced my stock '78 is relay-free, regardless of SOR and other showing fitment from '69-'80.

corsair23
08-09-2007, 12:50 PM
Steve,

It seems to be that if your horns have two wires going to them then you don't need the relay :confused:

Information taken from this MUD thread (http://forum.ih8mud.com/showthread.php?t=144218), post #18 specifically

SteveH
08-09-2007, 03:18 PM
Wow - never knew this. Thanks.

corsair23
10-09-2007, 04:15 PM
Forgot to follow up on this...

I replaced the horn relay (with a new OEM unit from CDan) and my horns work perfectly now :) - Occassionally I could get them to work with the old relay, but it like 1% of the time. I thought about taking the old relay apart to see if I can clean it up and get it to work...Probably never will though...

So, if one day your horns just go "brrrrrrp", and you have a relay, that is probably the issue :thumb: - Oh, and new OEM was cheaper than aftermarket IIRC

chume
09-07-2010, 12:02 PM
Hi,
I have the opposite problem on my 76 FJ40. After an inadvertent short from ammeter wiring in dash while replacing a brake light switch, I toasted some wiring :-(( Now my horn wont stop honking!

I did find some heat damaged insulation on wires to ammeter and spliced in new connections. Everything else works, but had to disconnect the wires to horns. I looked at wires coming from horn switch on column and no siges of any heat damage. Previous owner had installed an alarm system, so wiring under dash is a rats nest. Could a faulty horn relay or wiring at the relay cause the horn to continuously honk? I am an electrical novice, but trying to figure this out!!!

thanks

cliff

seattle wa
1976 FJ40 chev v8

Dr. Schlegs
09-07-2010, 02:18 PM
Anyone know where to get a nice clean horn button for the steering wheel? a 72 model?

corsair23
09-07-2010, 02:53 PM
I looked at wires coming from horn switch on column and no siges of any heat damage. Previous owner had installed an alarm system, so wiring under dash is a rats nest. Could a faulty horn relay or wiring at the relay cause the horn to continuously honk? I am an electrical novice, but trying to figure this out!!!

Did you check the horn button contacts themselves as well as the wiring in that area to make sure one of the wires isn't grounded out? As for if the relay could be causing the problem I would guess it could. A new OEM relay is relatively cheap IIRC and worth a shot.

chume
09-08-2010, 06:32 PM
thanks. will do some sleuthing this weekend.

cliff