2004 f 150 reverse lights don't come one

check all fuses. first!!!
then scan the PCM, <<<< stated here and world wide 1million + times.
OK the dash cluster has s cute PRNDL Display
and this display is acting pure wrong that means PRNDL is failing
there are 3 technologies here (yours is last one.)

• old cars have PRNLD switch bad.
• or PRNDL on box works, but the TCM sets the gear you selected
• but the box reads back wrong (solenoid read back or pressure switches wrong)

or the IP cluster comms are failing.

i will now read the manual to you, SM service manual
and no engine told by you, (hard nut that)

4R70W , has in fact the pressure feed back sensors in the box
with EPC, it PCM tunes the pressure called line main.
so the PCM reads back what you selected
then if the pressure sensors read wrong, the display shows wrong
it means the PCM In not happy with this transmission
and only scanned it to find out why it is not happy is the only clues and cures.
and this
digital trans range
DTR sensor completes start crank circuit with transmission in Park and
Neutral, reversing lamp circuit in Reverse, and neutral sense cir-
cuit (4x4 only) in Neutral. DTR sensor also opens/closes a set of
four switches monitored by PCM to determine position of manual
lever (P, R, N, D, 2, 1)

when DTR reads wrong so will the cluster cute PRNDL indiector.
my guess to you are ignoring the CEL, check engine lamp.
driving.? (check power train lamp it really means)

http://www.ehow.com/how_6016968_fix-2006-dodge-grand-caravan.html
Hi try this link the 2003-2006 are almost the same and the above link should help you to find the fuse. After you replace the fuse if it still does not work call your local dealer to find out if it could be a reverse sensor or reverse switch. Good Luck and don't forget to let everyone on fix ya know if this worked.

CODE PO705 IS DTR SENSOR TR SENSOR CIRCUIT MALFUNCTION. POSSIBLE CAUSES, DTR OR TR SENSOR CONNECTOR IS DAMAGED OR SHORTED, DTR OR TR SENSOR SIGNAL CIRCUIT IS OPEN OR SHORTED TO GROUND, DTR OR TR SENSOR SIGNAL CIRCUIT IS SHORTED TO VREF 5V, DTR OR TR SENSOR DAMAGED, PCM HAS FAILED.

I had the same Problem with my 1994 Trooper. I was smoking (painting with translucent black paint) my taillights, and when i put the back in, the reverse lights didnt work. In a seemingly unrelated problem, my gearshift indicator strip on the dash would only stay in park. The solution is that there is a sensor that measures gear shift position on the transmission, that relays the power to the reverse lights when reverse is selected. This sensor turned out to be corroded through and the wires surrounding it had corroded from the inside out. I recently got that replaced, and the problem was solved.

Might want to verify the switch operation by checking the 7 pin trailer tow adapter for the reverse circuit. This is a standard 7 pin RV type plug


The "reverse switch" is called the DTR ( Digital Transmission Range ) Sensor, and it is mounted on the side of the transmission. This also contains the contact for only starting the truck in park or neutral, so if that works correctly, I would take a SWAG that the reverse section of it is OK ( but that is a SWAG ).

You can check the 7 pin, if that reverse works, the DTR is fine and the issue could be at the rear of the truck with the splice ( which the trailer tow adapter also goes through ).
You need to drop the spare tire to get to the connector, it is a large multi pin connector, reverse is the Black w/ pink stripe wire.

The "reverse switch" or backup switch is part of the DTR ( Digital Transmission Range Sensor ) on the driver's side of the trans, about half way on the trans.
This has ( if memory serves me correctly ) 14 wires from it, as the neutral switch ( starting ) and reverse lamps are only part of the operation ( other parts include the SOTF for the 4x4 ).

BJB ( aka Battery Junction Box , engine compartment fuse panel ) fuse #5 is for the trailer tow reversing lamp relay & the trailer tow running lamp relay. This is to the normally open contacts on those relays, which is the circuit to the 7 pin trailer tow adapter.
- Have you checked your 7 pin trailer tow adapter for metal left in there from a trailer plug ?
If you pull those 2 relays and replace fuse #5, does the fuse blow ? If so under what conditions ( i.e. when the headlamps are turned on, or when the truck is placed in reverse ) ?

BJB Fuse # 6 feeds the park lamp relay & the headlamp relay for the autolamp function. This could be where the lights staying on it coming from, but I would have guessed just the autolamp would have stopped working.
When the parking lamps are staying on, is this with the main headlamp switch in the auto position, or with the switch turned off.

The blinking OD light is the transmission reporting an error ( trans sensor issue or the actuator circuits have failed ).

The 1st place to check for this ( which is somewhat connected to the BJB Fuse #5 ) is the DTR ( Digital Transmission Range ) Sensor on the side of the transmission.

Could be the DTR connector is gummed up with road dirt, causing an issue. Part of the DTR is for starting ( Neutral or Park acts as a switch ) and part is the reverse ( again acting like a normal switch ) the other parts of the DTR feed information to the PCM for shift control and for 44 ( if the truck is a 4x4 ) for shift operation.

Start with the DTR on the side of the trans, unplug the connector and clean it with contact cleaner, and the check on the relays above.

Please report back your findings as a comment on this problem.

Thanks

the sensor/switch is located on the transmission, it has 2 or more wires connected to it

I would check the bulbs, remove them and test with a DC power source ( DC power adapter to 2 wires Pos + Neg )

Fuse #14 has the reverse lamps on it, as well as the Day Time Running Lamps ( DRL ) relay coil, the shift interlock ( would not be able to take the truck out of park, while it was running ), and some other items I am missing at the moment.

If you cannot make the test harness to a DC power outlet, you can block the wheels ( at least 2 - front and rear ) on a level surface, turn the key to the run position ( do not start ) and place the truck in reverse, and check the bulb socket with a meter or test light to check for power.
If it is installed, you can also check the Trailer Tow adapter reverse circuit as well ( this is relay is triggered by the reverse circuit ).

If you do not have power at either ( don't forget to check for corrosion on the trailer tow 7 pin adapter ) this would be the DTR ( Digital Transmission Range ) sensor on the side of the automatic transmissions.

Have you used an aux backup lamp on the truck's reverse circuit ? ( not the trailer tow 7 pin adapter )
The DTR sensor and reverse circuit does not like 1 AMP additional load on it ( the lights will not burn at full brightness ) and if an additional load has been on them, the DTR sensor at the reverse contacts could be carbon'd up.