LX90

Well this is a new one for me and I am in need of your guys help. I just installed my autometer gauges in place of the center air vent. When we installed the gauges, they had no power, we disconnected the battery again and went trouble shooting the problem. We found out that the add a curcuit that we used blew its fuse. We changed that and now the car will not crank at all. The headlights, turn signals, hazards, horn all work, but the cluster gauges do not respond when we turn the key to the on position and the car does not crank. All the fuses in the fuse box are good. I have no idea whats wrong, or where to start trouble shooting next. Any help would be greatly appreciated. Thanks for all the help.

LX90

couple of notes. When the gauges had no power, the car was running. Yes the battery is connected.

silver91gt

where did you hook the wires to, and I am not trying to make you sound stupid, but the black wires are for ground, and the red wires are to a switched 12 volt source.


you may have a problem with the starter solenoid, take a screwdriver, and make sure the car is not in gear, and jump the 2 terminals with the screwdriver, it should turn over the starter, or click.

sometimes the solenoid sticks.
take off the battery cables and clean the battery posts and terminals.
it only takes 1 small short or even some moisture in the right conditions to corrode battery terminals.

LX90

All the wires are where they are supposed to be. The starter kicks over no problem. I'm thinking my neutral safety switch went out. It was acting funny a few times in the past. Anyone know how to bypass this and see if that is infact the problem? As far as my factory gauges not responding goes, aftering thinking back, they never responsed unless the car was on Lol, yeah I think I need to visit painless wiring for a new harness lol.

LX90

Ok here's the latest. We tried kicking over the starter and it cranks the car, but will not fire. We pulled the ignition coil wire off and held it to the AC compressor to see if there was a spark and there was no spark found. How could we hurt the ignition coil just by installing gauges? And is this a good way to test for spark? Thanks again.

HACKGT350

im pretty sure you shorted out your ignition box its also called a brain box. it controls the spark and all that good stuff. it is a little mettal box about as big as a video tape maybe a little smaller. go to the speed shop or where ever you go and ask to get a new brain box its like 30 bucks not much at all same thing happend with my car blew one thing and my whole electrical stuff was shot had to get a new volt reg brain box and alt. it wouldnt hurt to replace it anyway they go out with age

LX90

Where is the brain box located on a 90 stang?

HACKGT350

i have an 84 and it is on the drivers side of the engine bay under the softball size hole i guess its half way between the firewall and the front of the car its right before the strut tower if its not there its probably on the other side but im pretty sure its on the drivers side

chord509

My recommendation is to unplug the gauges and see if the car runs again. If not, start checking the ignition system with a voltmeter and find where the breakdown is. You may also put the voltmeter on the gauges and find out if they are what's causig the problem or if it was just a fluke.

silver91gt

there is no brain box on a 91.
in 1986 ford changed the motors to efi and got rid of the carb stuff


do you have any fuel?
when you put the gauges in if you took the cluster out, did you remember to plug in the 2 plugs in the back?
if you think its the neutral saftey switch, take it out and test it.
is it a 5 speed?
do you have a msd ignition

the easiest way to test for spark is to take out 1 spark plug and hold it to a ground, then get a buddy to crank it a little, you will see if there is spark.
wear gloves and dont touch the sparkplug or you could get shocked.