LOL, now we get the story, It's hyper flashing because the front signals aren't being connected to the flasher, in other words the flasher thinks there's a blown bulb. Totally expected for the flasher.

Despite what you might read, the hazard switch can not cause individual signal lights to malfunction. If the rears are flashing then it's not the hazard switch.

Check the light blue and dark blue wires at the MFS connector. They should cycle on and off with the flasher. If those work, then you have to go further into the fuse block and BCM wiring.

 

Thank you to you and Speedy 007 for suggestions. Do you guys think it's likely the used multifunction switch? I PMd you a few days ago, Lionel, about replacing the multifunction switch. I replaced it myself last year, but it is a used, unknown mileage/model year switch that would check out fine for a seller or buyer on the bench, because it works fine until something gets warm. I was told by a GM Tech at the Stealer I needed a new Multifunction switch, thats why I bought this used one. I bought a brand new Multifunction switch maybe 3 months ago, so I guess I better install it. As I said earlier, the front sockets have been cleaned, and new bulbs installed. I guess I'm going to have to install the new multifunction switch. It is a PITA, but I did have my valve guides replaced, set up my own valvespring installed height, and installed and torqued down my own heads last month. So I guess this wont be too bad in comparison. I had a bad fall in early July that permanently screwed up my left shoulder/arm. That's why the new switch isn't in, yet. I wish I could blame drinking, but I don't drink!! A second or two of carelessness, and down the stairs you go!!! I'll fix this hyperflashing one way or another. I really appreciate the help, guys. Thank you VERY much. I'll post up if the multifunction replacement fixes it.........

 

I would still think it’s the sockets even though you have cleaned . Clean isn’t new . What happens from experience with mine is.. the sockets themselves really aren’t the best quality ...and I have 1 aftermarket socket rigged in but it’s a market light still a bad marker light ,drl,or turn signal is gonna make hyper flash ...which side is hyper flashing ? Suggestions aftermarket get a new socket in there whether it can be disconnected or has to be cut it’s been a while since I looked at my turn lights so it’s a bit foggy what all in details but these t drl’s get hot and ruin sockets ,,,and the housings ...so of it happens to be a socket ...replacement bulbs get some led lights and you’ll have less worry about burnt up sockets ....


A video of what is going on would help further help us maybe Pin point it .. signal no lights on, Signal again with lights in 1st on position, signal again lights full on position, signal with brakes on ,,I bet someone here has narrowed it down quite a lot from that ...fact is you might have to cut some wires and re wire up a sockets or two ...at the worst ...


Lastly after u got it get som LED bulbs ,,and a hype flash thing from vette mods to eliminate future heat and burning up issues.


Or it’s more like what Lionel says and the the flasher you replaced is spent & heated up and no longer working reading inputs as it should ...very well could be....Either way if I have replaced it before it should be easier the 2nd time right ..and turn signal sockets really are a easy fix to ...good luck keep us posted

Lionel seems to know his stuff so def take some pointers from him...after all I did copy his rim size and it worked out fantastic. Well I think it’s him if I recall it right .

 

[QUOTE=grinder11;1602128125]Thank you guys, for helping. OK, I have some additional info. I have history codes of B2578, and B2583. Could this be the multifunction switch, or possibly ? Thank you again. From what Im seeing, these codes say it's a short to voltage. Hope this helps......

 

I found this for you on a old thread please look up some research plenty of it has been discussed..


From the Service Manual

DTC B2578 Right Front Turn Signal Monitor Circuit
DTC B2583 Left Front Turn Signal Monitor

The turn signal switch or the hazard switch is internally shorted or is sticking. So I was trying to say earlier it in the switch I should have been more direct and implied your signal switch or hazard multi switch 1 of 2 so it’s a 50/50 coin flip ...goodluck

 

@grinder11 Hello, Grinder! As mentioned above, since the rears flash, your hazard switch should be fine. If the problem were the hazard switch it would be affecting both, front and rear.


Why don't you perform the test suggested above before replacing the MFS again? It's very simple and you only need a multimeter. While engaging turn signals, first for the left and then for the right, backprobe the LT BLU (left) and DK BLU (right) wires from the MFS connector. They should alternate between 12V and 0V following the flasher. If they don't, then your MFS is not passing the flasher signal (from the PPL wire) to the front bulbs.

 

Schematic saved yup just in case down the road

 

Here's the complete schematic in case you need the whole picture

 

 

Thanks for the advice guys. Glad to hear from you GCG. OK, I decided to be a glutton for pupunishment, and installed the new MFS. Did it for 2 reasons-1: It eliminates the used MFS from it all, and-2: Since I've had it for 3 months, and it's an electrical part, I probably couldn't have returned it, anyway. Sadly, no difference. I have seen that when the hyperflash happens, just the rears flash fast. Let's say I use the left turn signal. When it hyper flashes on the left turn signal, the left rear hyper flashes, and the left front light goes out. Same thing on the right side. However, sometimes one side will hyperflash, and the other wont! If I signal right, and it hyperflashes, if I try to signal left, sometimes it works OK, but most times when one side does it, the other does too. I'll try the multi meter tomorrow, GCG. Speedy 007, I read the codes you posted. The codes B2578, and B2573 said short to voltage. But why isnt it ALWAYS shorted to voltage? Used to call these problems "morning glorys"!!

 

Trying to post on an older phone sometimes makes for interesting nonsense posts!!! Please bear with me!!!

 

Signal light column switch ...


https://www.partsgeek.com/gbproducts...SABEgL3nPD_BwE

 

Grinder, just a quick question to have more info.

When you're having the reported problem with the turn signals, if you turn off the turn signals are your DRL lights behaving correctly?

 

Yes, they are good as long as the turn signals aren't hyperflashing. Thank you for replying. I cant work on it anymore until tomorrow (Sunday). I'm starting to think Speedy 007 has it pegged with bad sockets. Like he said earlier, just because they're cleaned with new bulbs doesn't mean they're new. It seems to be heat related, and they ARE 20 years old. I intend to find out, for sure. Thanks again.....

 

One intermittent failure of one socket will not cause both sides to hyper flash unless someone fudged it up and crossed the wires on the same line then one spent socket will cause failure or in your case two spent sockets if wires are correct ...otherwise I would say the front relays in your signal switch are and had lived the days ....if u have to get a new switch at the days end I would recommend buying a ( new ) part. Because a used one will prob fetch 120.00asking and a new is only 190.00 bucks maybe 170 if U use coupons or whatever I can to get backs something ...I bet you’ll see the burn marks inside the old signal if torn apart where she blew ....at the front diodes aren’t actuating the front tap pulse so it’a flying all the power back to the rear flasher....hence hyper flash to explain so again is it likely u have 2 bad sockets ? Maybe it’s possible after 20 years they could have taken a big dump together but I would honestly myself suspect the switch ...but again I would have replaced the sockets 1st of all bulbs even the marker lights .....prob those sockets to there about 36.00 each 72.,150-175 on sockets and bulbs and another 180 or so on a switch ....at worst your prob 350 ish deep in it like that ...good time to think about LeD and pick up a hyper flash module from vette mods there about 40 bucks can’t remember but switch back led will save your signal housing lens for sure those drl get so hot I lit my cigarette off it one day no joke ....and melted a 2 holes around the socket Input so the bulbs would hang there waiting to catch something else on fire personal I think I should still be a recall on those housing and lights today fire hazard to say the least....I had to replace with the eagle style D.O.T stamped housing with some JDM switch backs led ..just something for to consider .....the more led you can throw at the front end of the car the better I have noticed the rear tails don’t really heat up ...but if u got fog lights as wel the h7 halogen in it gets super hot it will melt plastics ....so a led should be consider there as well and in the head lights ....in return u might just save your cars alt as wel a few years not pushing all that extra wattage out to catch your bumper on fire lol just saying ....kinda lost track there ...

 

But what happens to the DRLs when the problem IS present (front turn signals OFF and rear turn signals hyperflashing)? Do you still have DRLs?

When the problem is happening, before you engage the turn signals, both DRLs should be ON. When you engage the turn signals (let's say to the left) the right DRL should remain steady ON, while the front left goes OFF and the rear left hyperflashes. When you disengage the turn signals, the front left should return to its DRL function and be steady ON, like the front right was doing, and the rear left should turn OFF. Viceversa when engaging the right side turn signals.

Could you check that and test the LT BLU and DK BLU wires as mentioned above?

 

Indeed a 14.00 multi meter would solve and pin point it rather the trying to be accurate on guess work .

Heres a little trick try ....unplug the front bulb one side and signal see what u get

 

The question GCG has posted is very important. The DRL and front signals both use the SAME filament in the bulb. So, it's not the socket or bulb if the DRL works when the signals are off.

I HIGHLY doubt it's the bulbs or sockets anyways because both sides would have to "break" at the same time which doesn't make much sense.

Do the voltage checks both myself and GCG have asked for. These are the wires the BCM is monitoring and they should not be at battery voltage with the signals off.

Anything else on the car act up? I'm almost suspecting a BCM grounding issue.

 

Thanks for help guys. DRLs are fine.....UNTIL hyperflash occurs. Then front is all dark. I have the new multifunction switch installed. Still hyperflashing. I have a multimeter. So you guys are basically saying set it to DCVolts, ground black lead, then probe the 2 wires and check for 12 volts, alternating to 0v, then back to 12v again, right?
If I get to it today, it wont be until later this afternoon. Wife is sick now!!!! Seems this car repair is stubborn lol......

 

Yes, GCG, you have it nailed, I believe. Will test later today. At any rate, will report back ASAP!! Thanks to all for your help......