1991 honda accord ex. will not start, halo around the key comes on but no dash lights. everything else gets power. but dash light, and wont start. it cranks over, no start?

Hi, First check your battery connections (clean and tight) Second check battery for 12.5 VDC Use volt meter for this. Check and load test battery. If battery fails this test replace battery. Check fuses and relays. replace if necessary (bad) Hope that helps.
If you can not perform these test yourself. Take it to a mechanic.

Relay or fuse?

blown fuse.
the CEL lamp must glow, or the ECU is dead. (no power)
the CEL is very important lamp telling you the ECU has power
and it thinks(sic) that it is ok, (basics)
if the lamp is burned out, it become hard to work the ECU.
as this ECU flashes codes for errors,
check all fuse. in both boxes.

Does the engine sound like its turning over faster than it normally does?

When you turn the key on do all the dash light come on as they normally do?

Is there an anti-theft light on or blinking?

With the distributor cap removed, crank the engine and see if the rotor turns in the distributor. If it doesn't check to see if the timing belt is broken.

If it does turn check for power on the black with yellow wire in the distributor. If there is no power check fuse 11 in the fuse panel under the drivers side of the dash.

Let me know how that pans out. If you have any questions let me know.

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

Probably not the main relay. You either have a bad battery, bad battery connection, bad fuse, or bad ECU. If the lights on the dash don't come on, that's not good. See if your lights work on the car...that should let you know if you are at least getting power. Then check the fuse to the ECU. If everything checks out, you probably have a bad ECU.

You will need a wiring diagram of each circuit affected to trace the wires for a open in the system.

Check fuel pump fuse and all other fuses, check brake switch, Also, a worn ignition switch will cause the car to start sometimes but not always. Try turning the switch to on position, then jiggle the key around in the switch while pushing in a bit...now start the car...did it start? If yes, replace switch and/or key cylinder....

Turn it over have someone spray carb cleaner into the intake, deos it start now, please let me know.

You have to remove the console and radio pod. Then remove 2 screws that you can now get to behind the pod. Then pry out the dash light dimmer switch (the one you use to adjust dash light brightness) remove the screw behind it that holds in the gage cluster trim. Then there is another switch on the other side under the cluster (don't remember what it is) and there is another screw behind it. Have fun, LOL!

The main relay also controls the transmission and will cause an intermittent interruption of power and indicates its going bad. about a $60.00 replacement cost. the relay is located under left side of dash.