Airbag light fades on and off

I have 1996 Tacoma that is running good except- from time to time when I start it, the airbag light will be on, and stay on while driving. Other times it is off at first but comes on later. I figure this may be a wiring fault. But the weirder thing is it will sometimes slowly fade to off, then slowly fade back to on later. Other times it stays off as it should. There really is no rhyme or reason on when it goes on or off. I've tried correlating it to moving the steering wheel thinking it's related to a bad clock spring in there, but there seems to be no relationship.

I'm having a hard time thinking the fading is related to wiring but I've never troubleshot this system before. Has anybody seen this, and if so were you able to fix it? Anyplace I should start looking? AFAIK the SRS system on this truck is a couple sensors under the hood, the SRS ECU, and the airbag itself (no passenger airbag or shutoff keyswitch on 1996). What other pieces should i look at?

Thanks!

 

This happens on my 95.5

I think it has to do wth the clock spring

 

I'm going to try the DTC procedure in the service manual where the module flashes the light to indicate problems. However I'm guessing it won't show anything because if there was a problem the light would stay lit (in theory)...

 

the light must be on when you short the terminals, or else you won't get anything.

For 1995-1997 tacomas, the SRS system consists of only a driver airbag (no seatbelt tensioners or crash sensors). So your problem can either be a bad clockpring (very common), a bad ECU or a bad airbag

by the way, when the clockspring goes bad, it is usually accompanied by other symptoms such as horn not working and cruise control not working, and of course, the airbag light. If any of these symptoms occur when the steering wheel is turned, then it is definitely the clockpring

if you manage to pull the codes, post the result, I might be able to tell you what is the problem

 

oh and check your battery, as a dying or malfunctioning battery can sometimes cause all sorts of weird problems. Since the SRS system counts on the battery to operate normally, a bad battery can cause the light to come on. Same for the alternator

 

Horn and cruise work well which is why I haven't dug deeper on the clockspring front. Voltage slowly going up and down seems like it would point to the fading light. I'll stick my Fluke on it when I drive to work tomorrow and see if there is any correlation. Battery seems find (starts strong!) but alternator is original to the truck

 

My 96 just started doing the same thing. I haven't really looked into it. Totally random.

 

Then there is a good chance the clockspring is not the culprit.
Voltage spikes can be caused by either the battery or the alternator. Your alternator is 21 years old, so it wouldn't be a bad idea to check it (and the battery as well, just to be sure), to rule out any possibility.

Or there is something inside the ECU, like a capacitor, that is failing. If it is the case, you will have to get the ECU replaced. Unfortunately, a random SRS light is also a symptom of this :/ But let's hope it is not

 

My horn and cruise work as well.

I replaced my battery two years ago, guess I could check that and the alternator. Lemme find out how

 

check the charging voltage, like mentioned earlier if it spikes it causes problems. Do the headlights at night get visibly brighter when you rev the motor?

 

Hello, I am new at this site. I have a 1995 Tacoma with the exact same issue. Did you ever find out what was the problem? Any help is greatly appreciated. Thank you.

 

Mine does the same thing

 

Same here in my 96

 

Hey guys, for all of you out there. I found the problem to the issue above. It's the SRS Airbag Control Module. I decided to repair it myself since they are very expensive. I'll post some pictures once I receive the part I need to fully repair it.

 

In September, after sitting in the sun all day windows up on a 95-100 degree day, my A/B light (1995.5 model) started coming on, fading, etc without the key even in the ignition. Makes sense that it can since the clockspring has power with ignition key in off position.

I tried disconnecting/reconnecting the battery, but it would still come on, fade in and out, be off, then on again the next morning. I did nothing more and it went away after about 4 days. Hasn't happened since.

 

I have a long shot here, mine just started doing it after I had the lower dash panel off wiring up an aux. switch for some lighting. The srs light would be on constantly so I disconnected the battery and unplugged and plugged in all the connectors going to the srs system and made sure that they were clean connected properly and checked all other wiring under the dash. I retraced my steps of major things that I have done to my truck within the last 6 months, namely putting in the Scangauge which uses my obd2 port and going to led lights on the exterior. I unplugged the scangauge from the obd port and the light didn't come on and when I plugged it back in it would come on and then fade off. I am thinking the scanguage holds a little residual power and lights up the srs light for a few seconds and shuts off.
Keeping an eye on it.

Update: 8/28/2021, my solution is on post #22, still keeping and eye on it.

 

Not to bump this old thread... But I have the same issue. I suspect it's electrical, however, since it seems to coincide with the clock going dark or coming back on. It all started when I put a phone a charger in the cig lighter. Shortly afterwards, the clock went dark and the airbag light started flickering. I swapped out new fuses and it seemed to be fine after that (though the old fuse seemed to be fine too).

Anyway as a test, I tried putting a charger into the cig about a month later and it started back up again. It definitely seems that the clock and the airbag sensors are related in some way.... If anyone has any theories, it would be greatly appreciated!

 

So I actually had to have my horn worked on about 3 years ago but I don’t think it was replaced I think it was just some wires messed up. However right around the same time my air bag lights started flashing on and off sometimes dim randomly. Does that sound like the clock spring itself or maybe just wiring somewhere?

 

So I think I fixed it.

The cigarette lighter wiring had some wiring go bad and that was shorting out a lot of the electrical. I pulled the lighter and had it re-wired and ever since then, the lighter works, the clock stays on consistently every time and there's been no flickering/faded SRS light either.

Fingers crossed that was the only culprit.

 

How much work was it to do that? My clock used to come and go as well just like the airbag light I’m wondering if I should look into that as well