Electrical gremlins


nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
So I know many have experienced the gauge problems but I have a new issue. When I turn on the key... sometimes the radio, windows and door ajar and OBD will not work. I can wait anywhere from 30 seconds to a minute then it will come on ... once I hit the start button ... it all goes off again and comes on anywhere from 1 minute to a few minutes. I replaced those fuses ... 15a and 30 in the passenger footwell. Still happening. Any ideas??
 

fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
10,151
Belleville, IL
Check the ground strap, make sure clamshell and trunk are really closed, get new battery.
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
Ground... check. Been there done that. I’m double grounded!!!!
Clam and trunk... check
Battery.., that’s my gut!!! But no trouble starting... that’s been my only hesitation with replacing!!
 

RPM217

2005 white/blue stripe
Jun 18, 2010
1,465
Rye Brook, New York
Funny that you should mention that. I have had the same problem for awhile. I just spoke with Rich Brooks last week, and he told me he came across a similar problem with a car last week. My turn signals also don't work for about 5 minutes, and then come up. The radio, windows, come up in about a minute or two. Battery is good, ground is good, problem still driving me nuts!
 

Johntpr

GT Owner
Jan 18, 2017
139
Rockland County, NY
Odd things like this can sometimes be the fault of the smart junction box.
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
Where is the smart junction box??
 

2112

Blue/white 06'
Mark II Lifetime
Out of curiosity, how old is your battery?

I suffered a similar problem in a different car. I replaced the battery and it went away.
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
I’ve had the car 4 years and never replaced. It’s always on charger. I’ll try a new battery today.
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,308
The OPTIMA battery is good for 4 years and that's it.....They harden and implode.
EVERY 4 years replace it no matter what or suffer the issues......including spikes to gages.
ALWAYS take out the GROUND wire, clean the thread, sand the contact point then put clear nail polish over the bolt it to seal out moisture.....
100,000 miles 0n gts not including 1 billion miles on cp-1.
Don Carson had the exact issue at my house, we replaced the battery and it still went wonky, cleaned the negative cable and the car was like new...
Good luck
GTJOEY1314
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
Nope... not the battery!!

Does the smart junction box keep the tune?? I’ve got an aftermarket tune and I was just wondering.
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,308
Cable next...…..Mouse after that.....
gtjoey1314
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
New battery... double grounded... still the same!!!
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,308
check your batteries in the key fobs...…..
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,308
Wait Im old now..... tune is new? or 4 years ago?
Also check the clutch switch when you press it......
Ask rich on that one, did you put headers or a new starter ?
The wire melts if you put headers and its to close
Mice are a huge problem these days
going to bed report back
 

HighHP

GT Owner
Jun 3, 2019
89
Spokane, WA
Here is another great corrosion inhibitor. It's made for electrical connections and is used in your house on pure aluminum electric conductor wire connections. Pure aluminum is a great flexible conductor but it corrodes so this is used to inhibit corrosion. Lowes and Home Depot carry it. It is called anti-oxidant or corrosion inhibitor, and is sold in the electrical section. I have found that Gardner Bender OX-400 works the best, correct thickness, consistency, etc. It also comes in a tube that dispenses great. Some come in a squeeze bottle that don't dispense well and are too runny.
This works great on all electrical connections including battery posts.

 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
Tune is old. Nothing has changed on the car but this radio window glitch
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,308
So the car starts fine and runs fine.
Double check your key fobs, see if the buttons are crushed or stuck.
Change those batteries and your sure you cleaned the threads on the ground bolt and frame and all.
The ecu is so old by todays standards , we never had those issues compared to aston or land rover under Ford.
Good luck.....
Have you driven the car since the new battery to cycle the evap system and heat cycle?
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
Car starts and runs fine. No I didn’t drive it I just hooked up the battery. This smart junction box, what all does it do??

Thanks for all the advice. Best forum ever!!
 

gtjoey

Keep Smiling - GT Owner
Mark IV Lifetime
Oct 14, 2005
3,308
You have shed down relays in this car to protect systems if the cars electric is going down.
If you checked both key fobs and none are stuck and the batteries are new and read the car.
Drive the car for a bit and get a full heat cycle in the car to reset every thing.
After that, look for mice. , blow fuse? from mice …….
Drive it first , key on key off three times during the run...…..
Doabout 50 miles or so and make sure the gas tank is 3/4 or LESS TO KICK OFF THE EVAP CYCLE.
good luck.
gtjoey1314
 

nautoncall

GT Owner
Mark II Lifetime
Apr 6, 2014
975
So I’ve got a red top....do I replace with a yellow top or another brand battery??

Yes the “battery” question.

Joey thanks so much .