Replaced wire harness and ignition added a toggle switch b/c ig nition came with no keys i can get power to the toggle and blinkers and tail light but no head lights and cant get it to crank over and

Isolate the tail light wire, usually the brown wire going to the lamp assembly, then cut the wire and tie one end on one of the switches post and the other on the other post. You can find that wire coming out of the head light switch.

NISSAN SENTRA
http://alarmsellout.com/support/diagrams/vehicle/NISSAN%20SENTRA%201989-2005.pdf
http://www.ertyu.org/steven_nikkel/neonfsm/2000/EPL_8W.pdf

So If I understand, you turn on toggle and then use key to engage starter? Do brake lights and turn lights work, just not the running lights? Or are all tail lights dead. If none work, juice is not getting to the headlamp switch. Best fix would be to replace the probably bad ignition switch and repair wiring back to original, but quick fix would be to run a second wire from toggle switched side to the headlamp switch +

I hope you are only doing this temporarily. Generally speaking, ignition 1&2 would become powered when key is turned to on position. These could be wired to toggle switches. Highly recommend a high amperage momentary contact switch only for the starter lead. Best advice is the get a new ignition switch rather than mess with wiring. Doing so could do un repairable damage to your ignition system, wiring harness, and computer

he probably hooked up the toggle because the ign. swith was bad .the key turns the acuator which turns the switch . it sounds like you replaced the wrong piece . when you unhook the connector on the switch follow the wires to make sure he didn't cut the wire . hopefully he just added a wire to activate the solenoid . Good Luck

The front park lights work correct? If the front park lights work than there is not a problem with the light switch since the brown wire from the switch supplies power to the front park lights, front side markers, and the rear taillights. There should be twelve volts on the brown wire from the headlight switch with the connector plugged in and the park lights turned on. If this is true that there is a problem with the wiring to the back of the vehicle. A thorough inspection of the harness should reveal the problem. The dim break and blinkers support the above. High resistance also know as corrosion, in the wires or connections would cause this problem.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

It could be a bad multifunction (turn signal) switch. The way that switch works, it is possible that it can turn on the front blinker and not the rear one. It also cancels the brake circuit so the turn signal can work with the brake pedal depressed.

However, a more likely cause would be a break in the YELLOW/BROWN wire at the rear of the truck. It is common for the connector to get corroded at the left rear frame area where the bed harness connects to the vehicle harness. If you have trailer connections spliced into the wiring harness, these connections are also prime candidates for corrosion. I would look there first. Inspect these harnesses thoroughly all the way up and into the tail light assembly.

If the wires under the back of the truck look good, then I would check for power coming out of the turn signal switch. The wire at the turn signal switch is plain YELLOW (with no brown tracer). It is Pin (M) on the turn signal switch connector. The front signal is a LIGHT BLUE wire at the turn signal switch Pin (H). If you probe these with a test lamp, they should both work the same except the yellow wire will be hot with the brake pedal depressed and the switch NOT in the left turn position. If there is no power at the switch connector, replace the switch.

Hope this helps your out. I know the diagram and locator is a bit blurry but hopefully it gets what you need.
Drivers kick panel:
Front wiper 20A - Front wiper system Cigar 15A- Cigarette lighter Audio 10A- Audio, remote control mirror Air Bag 10A -Air bag diagnostics Stop lights- 15A -Rear brake light, high mounted stop light ECU B+ 10A - Shift lock actuator, transaxle controle module, radio, engine control module Room 10A - Interior light, clock, ignition key reminder, rear cargo area light switch ABS 10A- Anti lock brake system control unit ECU IG1 10A - Transaxle control module, shift lock actuator, ABS control unit, DRL unit Meter 10A - Instrument panel, back-up switch, electronics time control module, inhibit switch Turn signal 10A- Hazard switch ,front and rear turn lights, turn indicator IGN1 20A - Ignition switch ABS 30A- ABS pump motor TNS 30A- Tail light, license plate light COOL/FAN 30A- Cooling fan Cond/Fan 20A- A/C condenser fan Starter 15A- Start signal , Fuel pump Blower 25A- Blower Motor SR/ACC 10A - Ignition switch Hazard 15A - Hazard and turn signal light D/Lock 25A- Door locks ABS 30A - Anti lock brake system control P/W RH 20A- Power window motor right hand P/W LH 20A- Power window motor left hand IGN2 25A- Ignition Switch
Engine compartment :
Head 25A- headlights IG 2 30A- Ignition switch IG coil 15A -Ignition coil, condenser,generator IC regulator, diagnostic connector. O2 down 10A- Rear O2 sensor O2 up 10A- Front O2 sensor Fuel pump 10A -Fuel pump unit Injector 10A -Fuel injector ,camshaft positioning sensor, purge solenoid valve, EVAP, IAC actuator, Mass Airflow sensor, EGR stepper motor. fuel pump relay coil, vehicle speed sensor. A/Con 10A - A/C compressor controls, cooling fan BTN 30A- Brake light , high mounted stop light. Tail light LH 10A- License plate light, tail light , rear combo light, instrument panel illumination Tail light RH 10A-License plate light, tail light , rear combo light, instrument panel illumination Head low 15A- Headlight Head Hi 15A-Headlight Horn 15A- Horn

Inside kick panel

take your ignition to a good lock smith and he should be able to cut you another if he is any good