Q45 Brake Light Problem

Post by **emcnack** » Sat Nov 02, 2002 9:56 pm

I've got a brake light problem with my '90 Q.

The brake lights don't come on when I hit the brakes. However, the high mounted stop light does come on.

I've checked the fuses (found no problem) and replaced the 1157 bulbs with new ones. Still no brake lights.

The information center doesn't indicate that anything is amiss, i.e, there are no warning lights coming on such as "inoperative taillamp". Any suggestions?

:help

Post by **Q451990** » Sat Nov 02, 2002 9:56 pm

I'd do the check for the brake lamp sensor that's outlined in the service manual. Also, have you checked for voltage at the harness that plugs in to the socket assembly? You'll probably just have to trace everything backwards. It's common for the sockets to short out and blow the ILL fuse, but that typically takes out the shift lock function too, so you have to push the button near the shifter to get the car out of park...

Heath

Post by **maxnix** » Sat Nov 02, 2002 9:56 pm

Are all the bulbs in that circuit OEM? Has caused problems if they are not, as you will read when you search the threads.

Post by **Professor_Mike** » Sat Nov 02, 2002 9:56 pm

The signal for the 3rd brake light splits at the stop/tail lamp sensor to go to the 3rd brake light and remaining brake lights. A voltage check here would seem a good first step.

Post by **ligflava** » Sat Nov 02, 2002 9:56 pm

i seem to have the same problem. my brake lights don't work, but my third brake light on the factory spoiler works. no brake lamp inoperative warnings or anything like that either. one of the sockets is corroded and i've ordered new bulbs and sockets from the "everything infiniti" link. this is on a 1990 Q45.

if the brake lamp sensor was the problem, how would i be able to repair it? I've looked at "everything infiniti" and could not find a part corresponding to the sensor. any other ideas about where the problem might be? the shift lock is fine, no fuses are blown.

any help would be appreciated.

thanks in advance.

Post by **Q451990** » Sat Nov 02, 2002 9:56 pm

Call Joe at Infinti of Scottsdale (1-888-216-5328) - that's the real world http://www.everythinginfiniti.com

Some parts don't show up on the site yet.

Check the voltage at the connectors in the back with a volt meter to see if you're getting voltage to the socket assemblies.

Welcome to NICO!!!

Heath

Post by **natsoundup** » Sat Nov 02, 2002 9:56 pm

it's the part inside the truck about center with the keyhole...you have to pull out the liner.... it's bluish in color..

had to replace one in the 90 a couple of years ago.... I bought a little bit of time by removing it...and tapping it...which probably made the relay contacts work again....

Post by **Q45tech** » Sat Nov 02, 2002 9:56 pm

What relay contacts? The sensor is all electonic and measures the current of each bank of lights............bad bulbs = bad sockets = eventually bad sensor.

Post by **ligflava** » Sat Nov 02, 2002 9:56 pm

Q451990, natsoundup, and Q45tech: Sincere thanks for the quick and informative replies.

I will check the sensor with a voltmeter as soon as I can (unfortunately, med school doesn't give me much time to mess around with vehicle troubleshooting. I miss being an undergrad).

Once again, thank you for the replies.

NICO definitely gets two thumbs up.

Post by **Q45tech** » Sat Nov 02, 2002 9:56 pm

The metal loops inside the sensor are shunts across which the eleclectronics measure the voltage drop..........no voltage drop no bulbs working some voltage drop one bulb out [or high resistance in BULB or SOCKET...........more voltage drop both bulbs working per side.........too much voltage drop bulbs drawing too much current.

The voltage drop is sent to on board logic which sends an ok or a bad voltage signal to diagnostic display.

Different buls on different sides can sometime throw the self calibration out............a different voltage drop side to side.

The sensor is way too smart in someways.

When you change a rear bulb change all 4 at the same time as bulbs age and tend to change currents after years.......same with top mounted brake lights.........every 2 years would be a good replacement interval to save the sockets.

Change the sockets every 6 years........lots depends on how much night driving you do or braking.....8 bulbs are not expensive.

Post by **ligflava** » Sat Nov 02, 2002 9:56 pm

well, i got out the multimeter and checked the harness plugging into the stop/tail lamp harness. i'm getting the voltage coming from the brake pedal switch going to the harness, which is a relief. So i believe the problem is the stop/tail lamp sensor. I ordered one from Ralph at everything infiniti this morning (joe was off today). that and all my bulbs and sockets should arrive by the end of the week.

thanks for the help!

Post by **GseaQ** » Sat Nov 02, 2002 9:56 pm

Hi all,

It's been a long time away. Other circumstances have kept me inactive for the past year or so. I'm glad to see NICO is still alive and well - and thriving! Anyway, I had the same problem with my brake lights - hi-mount was the only one working. The bulb holders are like new and I've replaced all the bulbs 2 years ago and again last week. Last week was to try to fix the problem. 2 years ago the bulbs looked bad - contacts badly deformed and on 1 bulb the contacts actually merged - from deformity, not burning, although I'm sure there was some heat involved. This time there was noticable deformity on only one bulb, but not bad enough for the contacts to merge. Twice before I had the "Stop Lamp Inoperative" warning. The first time I replaced the faulty bulb, the next I replaced all of them. This time there was no warning message. I discovered the problem with a periodic light test.

My question to the members is: Did replacing the Brake Lamp Sensor fix the problem for you? Thanks.

Glenn

Post by **ligflava** » Sat Nov 02, 2002 9:56 pm

replacing the stoplamp sensor did the trick. just make sure you get the right one. i was sent a purple one, although my touring model required a green one.

joe wasn't the one taking the order.

good luck.

Post by **maxnix** » Sat Nov 02, 2002 9:56 pm

Glenn, gald to see you are back! Still see Paul (speckosand)?

I assume you used OEM bulbs instead of aftermarket?__________________Brian1995 Q45 & Q45t & 2000 Q45

Discover the power of the button!

Post by **GseaQ** » Sat Nov 02, 2002 9:56 pm

Hey Brian,

Thanks for the welcome back! Actually, no, I haven't seen Paul. We've been going through hell with our bloody airline industry (and Air Canada). Every day at work feels like hand to hand combat (figuratively speaking, of course). Paul is in a different department, but I'm sure his work life is no easier.

HOWEVER...the Q45 is GREAT for getting your head screwed back on straight after work.

Today, I had the radio turned up on cremate with 80's rock and the brake lights starting working again - albeit intermittently. Go figure...a Brake Lamp Sensor with good musical taste! The bass in the trunk must have given it a kick in the ***.

CIAO,Glenn

P.S. No, not OEM. But Sylvania should be OK for now for troubleshooting. When it's all fixed up I'll splurge for the OEM.

Q45 Brake Light Problem

Q45 Brake Light Problem

OEM bulbs?

Thanx

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