having trouble with OD light flashing, when truck first starts up the OD light cannot be activated by pressing the button. The light comes on only after the truck holds 1st gear without shifting and then OD light flashes in limp mode. I have been searching the posts as the speedometer and odometer do not work. I have changed the VSS in rear axle housing and unplugged and reconnected the dash cluster without any improvement.Can anyone tell me if there is a fuse or relay that might need to be checked or if the problem could be in the OD switch as it is damaged. Curious as to which circuit powers the tranny module. What else can I check and would anyone have the schematic for the truck, It's a 93 F450 IDI, no turbo. When you shut the truck down it seems to reset until you actually drive again. I have not been driving in this condition other than a couple of hundred yard on my street to trouble shoot and test. I had a problem with a short in the fuel heater blowing maxi fuse so I disconnected that for now, could this cause the loss of speedo and odometer? please help.
If the OD light is flashing then there should be a code stored. Your truck should be OBD I and you can either purchase a FORD OBD I code reader or using the link below, use an analog volt meter to obtain the codes. Then post back and we will see if we can help.
Try changing the relay for the transmission control module, When I change the relay it will be good for a month or two and then do it again. When you change the relay turn it off and turn it back on again if the OD light is flashing
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1994 7.3 idi diesel, 35" BF Goodrich tires on American racing rims, 3.55 axle ratio DEEZEE steps, DEEZEE toolbox, Custom aluminum backrack with CB antenna, Class 3 Hitch, Brake Controller,Transmission Temperature Gauge, E4OD, Bug Deflector, Vent Visors, Power Windows, Power Locks, Cruise, Tilt, JVC deck with JVC speakers, 346,000kms
I have been searching the old posts and am wondering about the relay more. When I got this truck it had a ton of shall we say improvised wiring for a plow, lights , sander etc. I went through and removed a bunch of butchery and I thought I was carefull not to just cut everything in sight. I tried to trace everything I removed back to the plow or till it terminated into thin air.
However there were some, I believe 3 relays that were taped together near the firewall D/s and they were just sitting on the inner fender loose. Also a couple of relays mounted on inner fender near D/S fire wall. It may be possible that i discarded the wrong relay. How and where would I ID the right relay and trace it back to the module or wharever it is supposed to go. I did leave the mounted ones and maybe 1 other in place. God only knows what they may have tapped into to get power and come to think of it this problem started just about the time I cleaned up the engine bay. If anyone has the schematic for a 93 F450 it would help.
I'll try the autozone site, just doesn't seem to be a ton of F450 specific info out there , 250,350 should be close. I picked up the OB II scanner, just havent had time to read the directions and pull the codes. this is a part time project but i would like to get it going. just don't want to put any money in the truck till I solve the trans prob.
I picked up the OB II scanner, just havent had time to read the directions and pull the codes.
Your truck is not OBD II...It will be OBD I . the Diagnostic link is under the hood, usually on the D/S near the firewall. If you look at the link I provided, it will show you a picture of the DLC. OBD II is usually under the dash and is a trapezoid shape.
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1994 F-350 7.3 IDI Turbo, crew cab, E4OD, LB, Dually Photos
ATS Turbo upgrades: 3" DP with 3" exhaust Magnaflow XL muffler: Pictures Here
1997 Jayco 323RKS fifth wheel w/2 slides, Air Lift 5000 bags
Pillar pod: Autometer C2 Series gauges: pyro,trans, boost, water, oil pressure
Hypermax Cowl induction, K&N air filter, flex-a-lite 26K trans cooler with fan,Tekonsha prodigy
Train Horns: Pictures here
my bad, I meant OBD I, went to autozone site, has very little on diesel stuff, even though I put my truck info in I'm getting distributors, and gas job stuff. Found wiring for diesel engine and chassis, But no diagrams for E4OD wiring, not even a hint. Can anyone tell me where this relay or fuse for the tranny is. On firewall, Power mgt, box??
Last edited by kolo : 05-29-2009 at 10:03 AM.
Reason: wrong spelling
The relay is in the fuse box under the hood it is relay #1
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1994 7.3 idi diesel, 35" BF Goodrich tires on American racing rims, 3.55 axle ratio DEEZEE steps, DEEZEE toolbox, Custom aluminum backrack with CB antenna, Class 3 Hitch, Brake Controller,Transmission Temperature Gauge, E4OD, Bug Deflector, Vent Visors, Power Windows, Power Locks, Cruise, Tilt, JVC deck with JVC speakers, 346,000kms
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