taillight problems Topic is solved

all2many · Post by **all2many** » 29 Jan 2018, 18:56

OK-- Taillights would go out when I started car. VIDA said CEM-8B01 now what to look for? grounds on CEM clean or ground on A pillar? Stuck on where to start any help out there?

Georgeandkira · Post by **Georgeandkira** » 30 Jan 2018, 07:41

I don't know what CEM-8B01 means but someone will be along with the definition.
Always provide mileage of your car. It frequently helps.

Are the taillights on before you start the car?
Try flexing the wires and see if the lamps flicker.
Are these misbehaving lamps in the fenders or in the trunl lid?

all2many · Post by **all2many** » 30 Jan 2018, 10:01

Thanks for insight. When I put ignition to position 2 I have taillights and able to have fogs on and plate light . When I start all taillights go out, and fogs will not go on. I still have brake and back up lights. So have a car I can only drive daytime as have no rear lighting and getting a ticket for lighting that I can not fix is the problem. Since I have tails in position 2 wonder if jumper wire of live lead wired to ignition 2 would bypass problem or cause other issues

all2many · Post by **all2many** » 30 Jan 2018, 15:08

just cleaned the grounds and vola! All is fine

Post by **mrbrian200** » 30 Jan 2018, 15:45

Which grounds where?

all2many · Post by **all2many** » 31 Jan 2018, 12:03

3 on each side of fenders but only lasted a day issue is back

Post by **mrbrian200** » 31 Jan 2018, 15:00

You talking up at the front doors or back in the trunk?

If it is a grounding issue I believe the grounds back in the trunk are what you need to be looking at. However, both sides have an independent ground wire. If all are going out at the same time the problem would point to the positive voltage supplied to the bulbs from the REM. Either in the wiring, a loose fuse or the REM itself.

I suspect it's the REM: left and right side tail lights are fed from separate wires on dedicated pins at the connector that plugs into the REM. So, if it were a wiring problem you'd see one side or the other go out, but not likely both at the same time. Sounds like a classic case of a bad solder joint or failing control circuit. By 05 the plug in relay was updated to either an internal board mounted relay or power transistor.

Only the park/running lights on the front of the car are supplied by the CEM. The rear tail lamps are supplied by the REM in the trunk.

all2many · Post by **all2many** » 31 Jan 2018, 15:49

Have you ever felt like DUH! Was going nuts trying to figure this out. Logic said all fine with ignition in position 2 so what if I try to jiggle it after starting back to that and it worked. Seems the ignition switch is not springing back so lubed it up and hope that works or I'll just replace ignition/

Post by **abscate** » 01 Feb 2018, 06:59

Definitely replace that ignition switch. Lube isn’t going to fix bad electrical connections

Post by **mrbrian200** » 01 Feb 2018, 08:26

Was anything else not working properly aside from the tail lights? If indeed the ignition switch was at fault, and only the tail lights were affected, that would mean there's a dedicated contact/wire running from the ignition switch feeding a lamp specific control signal to the CEM, LSM, or REM that is not represented in the electrical diagram.