I have a 1990 f250 7.3 IDI 4x4 with 96,xxx miles on it automatic.

1st question I have brake lights,turn signals but no running lights or headlights, I have tried searching for the fuse box diagram but no luck. could it be just a fuse or what should I try looking for ? Ive tried replacing dimmer switch no luck also no dash backround lights

2nd question My tranny is in limp mode ( i hope) only have 2nd, drive (4th) and reverse. tach is not working (ive read that will do it ?) There was a box plugged in by tranny but looks to have been run over and smashed what is that box ?


I appreciate any and all help I can get, Id love to get this thing going to put another IDI back on the road !

Thanks everyone

 

On #1 it may be the headlight switch. The brake and turn signals are serapate. The others al work off that switch.

#2 is out of my league lol. I really hate auto trannies lol.

 

i agree the headlight switch is probably the culprit with the lights.and as far as the tranny it could be the tach sensor

 

That is what I was thinking Rupe from reading on here but figured I would be way off lol.

 

ohh an btw gotitcheap90 welcome to FTE an the idi forum
it could also be the wiring harness to the headlight switch does it look burnt at all?

 

Ya welcome to the best forum on the site. The guys here a top notch nad will do everything possible to help a guy out.

 

The Tach sensor is the typical failure for a Tach, the Tach sensor is located on the housing near where you add oil, It takes a 1" wrench and has two wires coming out of it... Check the wires as they exit the sensor, are they cracked, if yes replace, it's a Ford item only and is not inexpensive.

-Enjoy
fh : )_~

 

looks like Im heading to my local pull-a-part haha Thanks for the input Ill be sure to check everything in the morning, the trucks got a few things wrong obviously but for 325 bucks delivered to my house I couldnt pass the deal up only rust is on bottoms of doors, also has the banks side winder kit,

Thanks for the welcoming, Ive learded quite a bit just reading these last couple of hours and love every bit of it !

I have heard theres a TECA sensor or relay that could be involved in why my tach isnt working ??

 

Won't affect the Tach.

-Enjoy
fh : )_~

 

okay thought I'd ask. Okay so I decided to check the few things everyones suggested, For my lights I tried moving the switch and trying to get them to work, no such luck so I am going to get a new switch tomorrow.

My tach I had checked the 1inch peice with the two wires, niether wire looked be broken,cracked or any thing noticabely wrong. Maybe this will help figure out the problem, when I bought the truck one of the guys had said the tach worked but only when over 1500 rpm, well i know for a fact I have had it over that to see if this was true but for me personally it will not work what so ever. So does this help diagnoss the problem any better it would only work above 1500 now wont work at all.

Thanks everyone for helping

 

the "TECA" will change how your tranny shifts

 

how does the speedo work?

 

That relay controlls power to the tranies brain. If your tac aint working thats why you are in limp mode. Do not drive it in limp mode it will destroy the trans. Most likely cause is the sensor as stated

If you cant find the diagram for the fuse panel thake a test light to both sides of each fuse and see if any are blown some times they look good even when they aren't. the switch is easy enough to test rather than just rplace use the same test light to see if anythings coming out of it

 

the speedometer works fine, also the reason i was asking about the diagram is a couple fuses are mising and I can see that somethings suppose to be plugged in.

Wheres the TECA sensor located ?