I have a very interesting situation! 06 mustang won’t start unless I remove fuse HELP!

Drum4life23

New Member
Nov 3, 2019
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Oakhurst
So I desperately need some advice on this one!! So I have an 06 mustang with a newer engine haven’t had many issues with it but recently my car wouldn’t start out of the blue! So I popped the hood and checked a few fuses and as I put about the third fuse back in from checking it my interior lights came on so I tried starting it and it started!! It only started about 3 times before it stopped starting/turning over. So I did the “fuse trick” again about 3 times it worked till now it’s back to not starting and the fuse trick doesn’t work but I am hoping that it will tell me what’s wrong So PLEASE HELP! Any one have any ideas???? Thanks!
 
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08GT500

Active Member
Jul 12, 2018
524
61
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Massachusetts
Hi, Do you have a security icon on your dash, it may be your alarm system. Do you have the spare key? Try that with nothing else on the ring at the same time. Check all your fuses, the one in the Smart Junction Box may blow. If you’re trying to start, verify you have the steering wheel locked so it doesn’t move first.
Has it rained recently before this occurred? Water makes its way into the smart junction box in 05’-07’ Mustangs. Look for moisture under the dash with a flashlight, check every fuse, check for power at the inertia switch at both sides, check your grounds, and clean your battery terminals
Try the wheel in a few positions. Then pull out the key & try to start again. Be sure the fuel pump is running for about 5 seconds when you turn the key to on, just before “start”. If you have a 5 speed, make sure the neutral safety switch is being hit when you press the clutch in to start it
The 05’07’ Mustangs had an issue with water getting inside the Smart Junction Box, make sure its bone dry inside the fuse blocks ‘ under the dash. Use a good. Flashlight, under hood/underdash.
Check the fuel pump inertia switch if it spins but no start.
The battery must be fully charged for it to start. Pull the terminals, clean the terminals again, check the grounds, battery to block, block to chassis, battery to chassis, battery to CPU. Remove each one, clean to bare metal, use an electrical contact dielectric paste & lock bolts down tightly, these have been known to have alternator grounding problems, jumper negative cable to battery negative to starter chassis.
Once running check for 13.8-14.2 V at battery terminals, should be at minimum, 12.0 volts at battery, just sitting there. Redoing these steps sucks, but it helps to get you reliably running.
Clear every computer code once car charges overnight, tighten clamps (+)/(-) very tight but do not overtighten.
Hitting the brake & holding it will clear codes once each FOB button is held in, each for a few seconds, last is unlock, hold brave in for 30 seconds after starting, use hour old FOB here, use the new one once you clean grounds, ensure all grounds are tight, Neutral safety switch, turn off security Lamp
May things repais that properly wornći works, make sure they are , post what you find, can reset PATS/FOB ‘
Good luck for now!
Starter relay costs 15$, buy a big package of fuses of type, mains for fuse holders & mains for fuse blocks
Talk to you later- John
 

08GT500

Active Member
Jul 12, 2018
524
61
38
Massachusetts
Hi, 05’07’s are notorious for this behavior, turn your steering wheel to lock and insert the key & retry, solidify all grounds including new battery posts, use a spare key with none other on the ring, verify all fuses as good, battery voltage sitting should bev12.0V minimum. 13.6-14.2 when alternator charges while running, Smart a junction Box is notorious for water infiltrating, open and verify this is bone dry, underdash/undsrhood water leaks inside with rain.
Grounding issues with alternator causes a floating ground issue, bond to Battery with negative to chassis, AWG#6 THHN. Every ground need be solidified, dielectric compound on all chassis grounds, CPU ground, Block to Chassis, Check Neutral safety Switch is operational under Clutch or Auto Trans, use other key & FOB to attempt to start engine, steering locked before key insertion, keep battery on float charger, verify car primes fuel system when switched to run, depending on what worked, that will be where the solution lies. What 5A fuse were joh pulling before when car responded?
Good luck
-John
 

08GT500

Active Member
Jul 12, 2018
524
61
38
Massachusetts
So I desperately need some advice on this one!! So I have an 06 mustang with a newer engine haven’t had many issues with it but recently my car wouldn’t start out of the blue! So I popped the hood and checked a few fuses and as I put about the third fuse back in from checking it my interior lights came on so I tried starting it and it started!! It only started about 3 times before it stopped starting/turning over. So I did the “fuse trick” again about 3 times it worked till now it’s back to not starting and the fuse trick doesn’t work but I am hoping that it will tell me what’s wrong So PLEASE HELP! Any one have any ideas???? Thanks!
Hi, My response(s) to your issue combined, is messy at best. Nonetheless, the content is correct. Water infiltration, ignition issues, charging system anomalies affected 05’-07’s. Any questions and I’ll be happy to help, or clarify Nohn, John