Odd short / ground issue when clutch is pressed 5.0 1991 mustang - Mustang Evolution

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Old 03-08-2019, 08:03 PM   #1
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Odd short / ground issue when clutch is pressed 5.0 1991 mustang

Hello

I am trying to trace a short when I press the clutch to change gears the radio goes off, kind of like the key was turned off it returns after I release the clutch, it doesn't not happen all the time here is what I have done

Ensured all wires were clear of the clutch and the path the clutch follows no wires were close enough I did put them in a plastic tubbing. Issue still occurs

Check radio connections, it's a factory Ford radio from 1991, all connections are good nothing rubbing.

Check the engine area to see if any wires where in the way of the clutch cable, not found

Checked grounds are clean or were cleaned to ensure a good connection

Anyone have any other ideas what or where I can check?

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Old 03-08-2019, 09:10 PM   #2
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That must be annoying when driving around town!

Is the car equipped with any aftermarket equipment such as an alarm system? Or is there any evidence of anything like that having ever been installed?
Does the factory wiring harness look like it is in good shape and unmolested?

With the transmission in neutral, will the engine start WITHOUT depressing the clutch pedal?
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Old 03-08-2019, 09:39 PM   #3
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Hi,

The car is stock the only thing I added an adjustable clutch cable when the original broke. All the wiring appears to be in good shape going to the radio surprisingly for being a 28 yr old car.

If the car is still in gear once the clutch is released it stalls and lunges forward before stalling.

The radio did this to me today for 5 mins of my trip yes it is annoying but it stopped turning the radio off after the 5 mins, heading back home after the car was off for about 2 hours made it half way and it started "shorting" again. I can not find any wires touching the cable or clutch pedal. I put it on ramps to verify nothing was touching under the car, I do not have any wires close on the same side as the cable.

Really has me puzzled as no wire is touching anywhere near the couch pedal, cable or under the car near the cable.

Also no other accessories turn off blower motor stays on wipers, I thought it may be shorting somehow with the ignition switch but only the radio goes off.
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Old 03-08-2019, 09:57 PM   #4
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I think that you misunderstood my last question.... Or maybe I misunderstood your answer.

Normally, as a safety feature, the clutch needs to be depressed in order to start the engine. I am curious if the engine can be started without pressing in the clutch. With the transmission in neutral, of course, to avoid having the car lunge forward.
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Old 03-09-2019, 11:05 AM   #5
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Correct I need to press the clutch to start the car, I tired for the heck of it to try to start it without the clutch depressed and nothing the switch appears to be working as it should.

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Old 03-09-2019, 12:16 PM   #6
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I suggest finding a good wiring diagram and focusing your attention on the circuit that the clutch safety switch is on, since this problem only occurs when the clutch pedal is being depressed.
I'm not sure how it interrupts the starter motor circuit, but if it involves the ignition switch, there could be a problem with the wiring harness that is inside of the steering column, or possibly, with the ignition switch itself, somehow affecting the power supply to the radio.

I presume that you have already inspected the fuse box, and verified that there are no loose fuses or anything else obviously out of place?
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Old 03-09-2019, 04:31 PM   #7
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radio

those radios have poor grounds try grounding the frame of radio direct to bare metal and check: engine to frame ground
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Old 03-09-2019, 06:27 PM   #8
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Quote:
Originally Posted by George of jungl View Post
those radios have poor grounds try grounding the frame of radio direct to bare metal and check: engine to frame ground
I will give this a try also, thanks

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Old 03-09-2019, 06:31 PM   #9
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Originally Posted by straybullitt View Post
I suggest finding a good wiring diagram and focusing your attention on the circuit that the clutch safety switch is on, since this problem only occurs when the clutch pedal is being depressed.

I'm not sure how it interrupts the starter motor circuit, but if it involves the ignition switch, there could be a problem with the wiring harness that is inside of the steering column, or possibly, with the ignition switch itself, somehow affecting the power supply to the radio.



I presume that you have already inspected the fuse box, and verified that there are no loose fuses or anything else obviously out of place?
I will look in my factory manual, I have multiple mustangs so figure this was a good purchase I appreciate you help and will check the safety switch wiring just odd it only does it intermittently I can go a day or two no issue but nothing in common when it acts up weather hot, cool rain no rain. I'm in Florida we don't really get cold just cool for us. I will let you know what if anything I find.

Thanks

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Old 03-10-2019, 06:48 PM   #10
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Radio cuts out

I believe your problem is in the radio not the clutch. When you are driving and you push the clutch in to go to another gear the car drops it’s front end. You have a connection either in the radio or on the back of it that’s your problem. Try another radio to see.

Just my 2cents
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Old 03-11-2019, 09:18 AM   #11
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Originally Posted by Charger212 View Post
I believe your problem is in the radio not the clutch. When you are driving and you push the clutch in to go to another gear the car drops it’s front end. You have a connection either in the radio or on the back of it that’s your problem. Try another radio to see.



Just my 2cents
Thanks I have other stock radios I will try this also, drove car this morning no issues it's one in a while which makes it harder to find the issue as it doesn't do this also the time.


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Old 03-12-2019, 10:24 AM   #12
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I think I found the issue, today I had the radio low and when it occurred I heard relays clicking from the fuse area, I took the seat out so I could fit under to get a good look and found the hood cable missing some plastic coating I also found a metal barb on the clutch pedal I filed it flat and electrical taped the hood release cable. I will let you know if this fixed it pretty sure it will. I wanted to post what I found in case someone else has this issue.

Thanks for all you help

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Old 03-17-2019, 09:05 AM   #13
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Just curious if you've got an update for us?? Did your fixes turn out solving your issues??
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Old 04-05-2019, 07:32 PM   #14
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I think I found it, I dirty ground on the steering column as when I would push or pull on the column to get in or out of the car it did this also, cleaned ground area on column and reattached so far so good. I will reply if it occurs again

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Old 04-06-2019, 10:07 PM   #15
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Good to hear.If the problem does reappear,I wouldn't rule the ignition switch or it's harness pigtail out until you thoroughly inspect them.The ignition switch has numerous individual circuits inside it and it is possible for a few circuits to be shorted inside the switch while the remaining circuits continue working without issues.There was also a TSB back in the day for the switch & pigtail.They are well known for being troublesome & shorting out.Some wiring also runs from the ignition switch to the clutch safety switch,so they are tied together.The ignition switch diagram below shows which fuses & circuits are powered by the switch.
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Old 04-28-2019, 04:26 PM   #16
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Thank you

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