Electrical Horn/cruise Control Don't Work, But Fuse Is Fine?

revcor

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I've tried searching for similar issues, but all I've found so far involve the fuse blowing. Ever since I got my '89 Fox, the horn, cruise control, and cigarette lighter haven't worked. I never paid much attention to it. Recently I decided to try to figure it out, and checked the fuse panel and the fuse for the horn/cig lighter was missing. I got the proper fuse, installed it, and when I tried the horn, it honked for a split second then went silent. Repeated presses of the horn just yield a "click" noise (similar to the sound of a turn signal flasher). Cruise control still doesn't work. But the fuse isn't blown, it looks fine. Anybody experience anything similar or have any ideas?
 
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LiquidStangs

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Mine came with a busted horn (among many other problems). In my case, the actual horn assemblies were so badly rusted, they fell apart in my hands when I removed them. Replaced both with new ones from LMR, and everything's working fine.

When mine was broken, it acted just as you describe: nothing but a clicking noise when I pressed on the steering wheel. The fuse was OK in my case.

The actual horns (there are two) are attached in the driver fender well by the washer fluid reservoir. Its wiring comes off the driver side headlight.

Haven't tested my cruise control yet. My cigarette lighter works fine; I use it to charge my phone. Mine is an '89 GT, by the way.
 

TOOLOW91

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I had the same issue. Ill bet if you unplug the cig lighter it stops popping the fuse. check if there is change or something in the cig lighter causing a short to ground.

Cruise control could be a bad amplifier , could be a vaccum issue. Few things to check there.
 

revcor

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The fuse isn't popping the fuse is fine. I was just guess guessing that the horn issue and the cruise control issue were related because they're both on the steering wheel. I assumed it was most likely some issue in the wiring or connection from the steering wheel back into the dash. Particularly odd was that after I installed a fuse, when pressed the horn sounded for a fraction of a second then went quiet. But fuse didn't blow. I'll test the cigarette lighter and see if it works too, and take a look at the horns themselves.
 

jrichker

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The horn circuit has a button that supplies ground, a relay that uses the button to switch the horns on and off, and two horns. The relay reduces the current that the horn button has to carry. This makes it possible to use a small and simple switch and slip ring on the steering wheel.

Note that the horn ground is built into the horn mount bracket, so the horn must be mounted on metal with a good connection to the car body.

attachment.php?attachmentid=50337&stc=1&d=1178980490.gif





The horns typically develop an internal short to ground, which causes the fuses to blow. :eek:

The horns are located under the car on the driver's side, forward of the front wheel well. Disconnect BOTH horns, replace the fuse: if the fuse blows immediately, the problem is most likely in the cigar lighter circuit. If not, then press the horn button on the steering wheel: if the fuse blows the problem is in the wiring between the horn relay and the horn. If doesn't blow when you press the horn button, connect ONE of the horns and try again. If it still doesn't blow the fuse, connect the other horn. Chances are that the first horn you re-connect will blow the fuse. Whatever horn blows the fuse at this point has an internal short and is trash. Time for a trip to the junkyard... :crazy:

Horn does not honk, but does not blow fuses:
Run a jumper wire from the battery positive terminal to the horn input connector: the horn should honk. If it does, then your problems are in the other parts of the circuit. If it does not honk, replace the horn.
Use a test light or voltmeter and connect one lead to the horn wire under the fender and the other to ground. Push the horn button: you should see 12 volts or the test light will turn on. If it does not, check the fuse. If the fuse is good, check the relay.

The relay will click and honk the horn if you short the Yellow/Lt Green wire to ground. If you have a test light connected in place of the horn it will light. If it does not activate the horn or test light, look for 12 volts at the Lt blue/white wire. No 12 volts at the Lt blue/white wire, you have fuse or wiring problems in the circuit that supplies the 12 volts to the relay. Good 12 volts at the Lt blue/white wire and the Yellow/Lt Green wire shorted to ground and no honk or flash of the test light, replace the relay.

The rubber foam usually deteriorates over time and that is what makes the horn switch fail. Take it apart and replace the foam with some from packaging material. A little creative engineering may be required, but you can do it.
 

TOOLOW91

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The fuse isn't popping the fuse is fine. I was just guess guessing that the horn issue and the cruise control issue were related because they're both on the steering wheel. I assumed it was most likely some issue in the wiring or connection from the steering wheel back into the dash. Particularly odd was that after I installed a fuse, when pressed the horn sounded for a fraction of a second then went quiet. But fuse didn't blow. I'll test the cigarette lighter and see if it works too, and take a look at the horns themselves.
I mis read the end of your original post then sorry bud it was a little late . lol


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate
 

revcor

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I'm fiddling with it right now, testing the different things jrichker suggested. Power is getting to the fuse, because I realized that one of the horns was disconnected and pressing the horn yielded the clicking noise (meaning the other horn wasn't working for some reason but didn't have an internal short to ground), so I reconnected the second horn, pressed the horn button and promptly heard the pop of the fuse blowing. So what I know so far is that one of the horns has an internal short, and that's presumably why it was disconnected. But that doesn't explain the other horn working for a split second when I first installed a fuse and tried the horn yesterday and then going silent, or why the cruise control also doesn't work.
 

revcor

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Update: I have determined that neither horn works. I removed them both, and ran a jumper wire from the positive battery terminal to the spade connector on the first horn (the one that was previously disconnected) and connected the bracket to the negative battery terminal. Nothing happened. When I did the same with the other horn (the one that was connected and made a brief noise then went silent when I first tried it yesterday) it didn't make a noise but there were small sparks at the jumper wire - horn connection and the jumper wire - positive terminal connection. Maybe when I installed the fuse yesterday and pressed on the horn, one horn being disconnected led to too much load running through the remaining horn and blew out the insides (or whatever happens to horns)? So I definitely need new horns. The horn power wires are both showing 12v when the horn is pressed. If your horns go bad but all the wiring is fine, can this affect the cruise control? Or does that mean the cruise is a completely separate issue?
 
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jrichker

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The cruse control is a separate problem. Check both the vacuum valve on the brake pedal and the clutch switch on the clutch pedal. The vacuum valve opens up and lets air in and that turns off the cruse control. I do not have a diagram for the cruse control at this time, so I can't tell you very much about the clutch pedal switch.
 

pats91

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Another issue with the cruise is the cruise servo itself. I have had several times where the cable attachment on the cruise servo diaphram break. I would check the tension of the cruise control cable at the throttle body, and if it is still tight, check those items jrichker suggested.

This a good site for checking out the cruise on older ford cars: http://www.thorssell.net/hbook/ccmain.html
 
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Dobsworld

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I have an 88 LX convertible with horn and cruise issues. All fuses were good throughout the problems. The horn and cruise control would work intermittently together. If one didn't work, neither would. They worked less and less over time. Now the car itself has started shutting off just like I turned the key off, as I am going down the road. Slap the top of the steering wheel a couple of times and it fires right back up. Thoughts?
 

jrichker

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Bad ignition switch...

Recall on Ford Ignition switches:

Revised 7-June-2014 to add Torx bit picture and source. Also added replacement ignition switch wiring pigtail picture, part numbers and sources.

Some of the symptoms of ignition switch problems are things that don’t work or are intermittent like radio, turn signals, wipers or heater.

There was a FREE recall on Ford ignition switches. They overheat and sometimes catch fire. That burns up the steering column and sometimes the car interior. Since this is very old information, you may not be able to get the switch replaced for free anymore. The auto parts stores sell the switches for $13-$15.







While you are working on the switch, check the wiring and connector closely. A replacement connector with new wiring pigtails is available from most auto parts stores

AutoZone and Advanced Auto Parts have the same Part Number: 434 - may have to order, not always in stock

Advanced Auto Parts alternate part number: PT5534



Saleen0679 was nice enough to dig this up for us awhile back: How to replace ignition switch on 1979-1993 Mustangs.
http://www.mustangandfords.com/how-to/engine/5657/


Torx bit set from Advance Auto Parts



Autocraft torx bit set – have small hole in tip for tamper proof screws.
Part No. AC571/W1386 Cost approx. $12 +tax

Diagrams courtesy of Tmoss & Stang&2birds

Ignition switch wiring
IgnitionSwitchWiring.gif


Fuel, alternator, A/C and ignition wiring
fuel-alt-links-ign-ac.gif


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pin out
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif

93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif

Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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You may have two problems here. :shrug:
ignition switch as jrichker mentioned for the shutdown issue
clock spring issue for the cruise and horn problem issue
I would swap the ignition switch first.
 

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