Various Idiot Lights and Intermittent Symptoms

Here’s the story.

Drove it home and parked it for a month. Insured it and took it on the road. After a few days it felt like the transmission was slipping and in too high a gear, pulling away from a stop. Added some fluid, which seemed to fix it. On the way home, various “idiot” lights started flashing. Pulled to the side of the road, shut off the engine, let it sit for five minutes, then restarted. That seemed to fix it.

But it got worse.

For the last three months, various “idiot” lights would turn on, sometimes intermittently, sometimes permanently, sometimes individually, sometimes all together - traction control, low coolant, air bag warning, battery warning, check engine, ABS etc. The transmission stayed in third gear on one occasion. Cruise control would work intermittently, then kick out.

Two weeks ago I hit a deer. Now, to all of you who have never hit a deer, don’t tell your insurance company you hit a deer. Tell them the deer hit you. And don’t swerve to avoid it, hit it straight on. If you swerve to avoid it and wrap your Riviera around a tree, they won’t pay out. One of those little lessons that comes with age and wisdom.
Last week, all of the previous happened, plus some exciting new symptoms. Cruise control quit altogether and third gear was now permanently the only gear available.

Friday afternoon, all of the above, plus the radiator fans quite working and the engine overheated. Being constantly in third gear didn’t help of course.

Friday evening – get this. Everything worked perfectly. Yes! Absolutely everything. Even cruise control came back. Transmission shifted like a dream. Radiator fans hummed. Oh, except for one thing, the battery warning indicator, which, being used to warning lights I happily ignored. Fifty miles from home, things around me and on the road ahead were getting progressively dimmer and dimmer, but… everything else was still working!

Until five minutes from home, when all of a sudden, the dashboard lit up like a Xmas tree again, it kicked out of cruise, and the transmission shifted into third. When I parked, the battery was dead.

Paid $2,400 for the car. Break it to me gently. Tell me what to tell my local mechanic. Don’t get too technical on me. A solemn burial in the local graveyard is not an option... yet.

Kevanski in Western Canada

Is the battery in good condition? The security system is constantly draining it, and will ruin the battery if the car sits too long (like at a dealership?). It took me two batteries and one stranding to figure out how bad this problem is.

Thanks for the suggestion. The battery is on charge at the moment. I noticed the case bulges out slightly on both ends. I can get it tested on Monday. You think that could cause all those problems???

Check voltage at the alternator or battery terminal up front. Your symptoms seem to suggest a high voltage situation. If over 15 volts while running, the alternator needs replacing/rebuilding. I think the high voltage could also damage the battery, causing the bulging you mention.

Read this: https://rivperformance.editboard.com/t7112-alternator-failure-voltage-spike

See any similarities?

That certainly sounds similar - dash lights, transmission - I'll put alternator and battery on the list to check first. I hope it's that simple!

Incidentally, the battery is an AC Delco 79-6Yr, S/N 110944. There's another number printed (not stamped) sideways on the decal in the top RH corner - 0A081018. None of these numbers seems to correspond with AC Delco's date code system.

Oops! That top RH corner number reads 0A081018 then 12/07. To my simplistic mind, that might mean December 2007. Nah, that's too obvious!

A basic running voltage reading off the battery terminal block under the hood takes about 20 secs to do. Battery warning and SES lamps are both possible indicators of alternator failure. Get the SES lamp checked with a free scan from a local parts store. There's a good chance it will show a DTC 'system voltage' code.

If that's not it, you can cross the alternator off your list, and the scan will reveal another DTC pointing to your problem.

Appreciate your patience! Please excuse my ignorance! Battery terminal block? SES lamp? DTC 'system voltage' code?

Assuming we're talking about a '95+ Riviera, there is a small terminal on the passenger side of the engine bay, near the engine mount and drive pulleys. It says "Battery +12V" or something like that. You can pop open the plastic door and you'll find a hot connection that connects to your battery and alternator - it is a convenient place to connect for a jump start, or to get a voltage reading. Remember to test with car running, and keep clear of those belts and pulleys!

SES lamp is the proper term for "idiot light" on GM cars. SES stands for "Sevice Engine Soon". Lamp is the correct term for an indicator or bulb. "Light" is what the lamp does when voltage is applied.

DTC stands for "Diagnostic Trouble Code". In all cases, when you see the SES lamp illuminated, there is a DTC responsible, and it is stored in the OBD II memory. A scanner or code reader tool plugs in under the dash and tells the operator what caused the SES to light up.

More learning about automotive acronyms: https://rivperformance.editboard.com/t480-automotive-acronyms

Usually, when the SES is on, diagnosis is easy. The car is saying "here is what's wrong, fix me!" Interestingly, so many people ignore what the car is trying to tell you, instead trying all sorts of blind fixes that may or may not remedy the issue. Starting now, don't be that guy!

OK, I understand. Very helpful...!

So to summarise, check the voltage at the terminal block under the hood with the car running. If it's putting out, say, 17v, it could be the alternator or the regulator, so repair or replace either. If the voltage is normal (13-14v?) both are OK, so check the battery.

I assume, if the battery has been blasted with 17v for 3-4 months, it may need replacing anyway. With all that voltage pressure, it's not surprising the end of the battery case are bulging out!!!! But I'll try the alternator and regulator first.

Incidentally, the alternator looks very clean compared to everything else under the hood, so it's possible it was replaced fairly recently. Not to say it could still be faulty.

Thanks Aaron, and I'll keep you posted on what happens next week.

My first alternator lasted 35k miles, the 2nd lasted 170k. You never know with these things, they can go out at any time. If the battery case is bulging out as you say, I'd replace it regardless after you find out what's wrong.

The Optima Red top is a good quality replacement we've found will fit under the rear seat. This option is about $130 and does away with the need for the OEM vent tube system. AutoZone sells these, often with a $20 mail in rebate. See write-up on installation:

https://rivperformance.editboard.com/t4497-write-up-installing-the-optima-34-78-red-top

Good suggestion. I just finished researching Optima batteries. They look good, but couldn't find a local dealer in Canada, so I'll call them on Monday. Yeah, that OEM vent tubing is broken and so not functional, but fortunately no signs of corrosion in the battery compartment.

AA wrote:

My first alternator lasted 35k miles, the 2nd lasted 170k. You never know with these things, they can go out at any time. If the battery case is bulging out as you say, I'd replace it regardless after you find out what's wrong.

The Optima Red top is a good quality replacement we've found will fit under the rear seat. This option is about $130 and does away with the need for the OEM vent tube system. AutoZone sells these, often with a $20 mail in rebate. See write-up on installation:

https://rivperformance.editboard.com/t4497-write-up-installing-the-optima-34-78-red-top

AA happens to like Optima batteries. Which is OK but you could save $$ with no penalty in performance by getting a Group 79 (the stock OE size) with vents --Just saying - the stock battery (a Delco) if there are no electrical problems will last 7-11 years under normal use. My first battery lasted 9 and I replaced it only because it tested too low CCAs on a 'stress' test, but had not actually failed yet.

So again -- just saying - it would not be a waste of time to Shop around (INCLUDING local GM dealers, Walmart, Interstate Battery) for a "Group 79" battery. . And when you get that battery **be absolute sure** to either get the vent tubing or re-use your vent tubing and vent it thru the floor just like stock. Or else the fumes **will** eat out your floor quickly. GM had a TSB on this - when these cars were new it took ~1-2 years only to rot out the floor with a misvented or not vented battery.

Edit -- the vent tubing is available through GM dealers and not that much $$. Some battery places will have it as well but you'll have to ask. If your tubing broken means it's apart but all the pieces are there, don't fret just use a little smear of RTV at the connections to hold them together and reassemble.

Sounds to me like the alternator quit on you. It will be interesting to see what you come up with.

I have a bit more info.

I had the battery on charge for 24 hours, but it didn't hold the charge. I just drove it a few blocks, the battery warning light was on from the start, but everything else worked perfectly, except things like the windows and wipers were slow of course. Got close to home and not surprisingly, everything started to fail again, including the speedo and tach falling back to zero this time. Finally the engine quit dead two blocks from home. So it will be a new battery tomorrow, and then I'll get the alternator output checked.

I live in a small town and no second vehicle. The nearest city is far away, so I'll have to settle for whatever I can get locally. Thanks for the tip, I'll try to get a "Group 79" battery... and maybe new vent tubing... or duct tape the old one...

I think you are doing things backwards. You need to check the alternator first. A simple voltmeter check that will take less than 30 seconds. Do you know anyone with a voltmeter? To me, the battery warning light you are referring to means the alternator is not charging the battery. Putting a new battery in with a defective alternator will just discharge the new battery. If you replace a defective alternator, the engine may not crank, but it will start with a boost, and it will continue to run indefinitely off the alternator.

I agree with you, and you may be quite right about the alternator.

However, by the time I've paid for a boost and/or a tow, I could have paid for half a new battery, which I know I need anyway (because the existing one won't hold a charge). Then at least I'm mobile, I can drive straight to the local shop, they can test the alternator for me, and replace it if necessary.

Is it possible the battery light is permanently on because the battery is fried and it simply won't accept a charge?

At first I was thinking a bad connection in the dash, but I think you're on the right track with battery and probably alternator.

If battery and alternator test out okay, check your ground connections.

bigdave wrote:

If battery and alternator test out okay, check your ground connections.

I echo that sort of - I'd say, if you've never cleaned your ground connections, do it whether or not the battery really. is good. Main ground under rear seat; chassis starter ground on front passenger side box member (near starter - this breaks unless you hit it from underneath with Deep Creep or other penetrating oil)ground under ICM, ground on firewall. If you ever have the front kick panels off in the passenger compartment, clean the grounds there too. You can slow down further corrosion of the grounds by painting them with antiseize, conductive grease (NoAlOx) or dielectric grease (tuneup/connector grease) before reassembly.

Just saying - cleaning the grounds gets rid of a LOT of electrical gremlins. Great call Dave.

Albertj

kevanski wrote:

I agree with you, and you may be quite right about the alternator.

However, by the time I've paid for a boost and/or a tow, I could have paid for half a new battery, which I know I need anyway (because the existing one won't hold a charge). Then at least I'm mobile, I can drive straight to the local shop, they can test the alternator for me, and replace it if necessary.

Is it possible the battery light is permanently on because the battery is fried and it simply won't accept a charge?

Wow, I have a jump pack that I bought years ago. Keep it charged up on house current. I've used it about twice, but I can't tell you how many times I've boosted my neighbors in the winter when their cars won't start. Never take a dime.

That battery light tells you the alternator is not charging the battery. That's it's purpose. When you kept driving with it on, you ran the battery down to nothing. You are lucky you weren't driving an older car. One of my friends had one of his friends driving his Concourse restored 1970 GS455 Stage1 back from N.J., while he towed another one of his show cars. (87 GN) The alternator light went on, and he kept driving the car. The alternator belt had come off, and that belt also drives the water pump. The engine overheated to the point where the engine was complete junk. This was a numbers matching motor. Needless to say, they are no longer friends. They don't call them idiot lights for nothing. That could have also happened to your Riviera. There is one belt that drives everything but the supercharger.

LARRY70GS wrote:

kevanski wrote:

I agree with you, and you may be quite right about the alternator.

However, by the time I've paid for a boost and/or a tow, I could have paid for half a new battery, which I know I need anyway (because the existing one won't hold a charge). Then at least I'm mobile, I can drive straight to the local shop, they can test the alternator for me, and replace it if necessary.

Is it possible the battery light is permanently on because the battery is fried and it simply won't accept a charge?

Wow, I have a jump pack that I bought years ago. Keep it charged up on house current. I've used it about twice, but I can't tell you how many times I've boosted my neighbors in the winter when their cars won't start. Never take a dime.

That battery light tells you the alternator is not charging the battery. That's it's purpose. When you kept driving with it on, you ran the battery down to nothing. You are lucky you weren't driving an older car. One of my friends had one of his friends driving his Concourse restored 1970 GS455 Stage1 back from N.J., while he towed another one of his show cars. (87 GN) The alternator light went on, and he kept driving the car. The alternator belt had come off, and that belt also drives the water pump. The engine overheated to the point where the engine was complete junk. This was a numbers matching motor. Needless to say, they are no longer friends. They don't call them idiot lights for nothing. That could have also happened to your Riviera. There is one belt that drives everything but the supercharger.

and for what it's worth - if anything - alternator replacement on the Riviera is pretty straightforward. If there might be a complication I'd think it's if you get an alternator that does not already have a pulley on it you'll need an (air) impact wrench to get the old one off and install it on the new alt. It's so straightforward I don't even think we have a write-up on it, on this site.

Here's an update. It needed a new battery AND a shiny new alternator. Why both? The battery was old and the mechanic said the alternator was a cheap rebuild. He thinks the old battery was in bad shape, so it might have made demands on the alternator that fried it. He said the alternator was only putting out 7v.

The new battery is an AC Delco with a six-year warranty ($195) and the alternator is a Bosch ($320) covered by a 2-year roadside assistance warranty. Ouch and ouch again.

Incidentally, he said the previous owner had bypassed the heat sink in the battery compartment to avoid replacing it (the heat sink), apparently an expensive item. He said it was OK to leave it that way, but said the battery warning light would go out first when the car is started, but then come back on and stay on permanently. I can live with that, at least for a while, knowing that I have a brand new battery and alternator....

Didn't get to test it out. It went straight to the body shop to deal with the "negative impression" the deer left in the hood and grille.

I'll post again when I've put a few kilometers on the car in a week or so, and I'm satisfied the problem's solved.

In the meantime, assuming it's all fixed now, sincere thanks so much to all of you Riviera lovers for your help. It really is appreciated. I wish I had the same technical know-how that you guys have! But then I wouldn't be able to entertain you with my ignorance of electrically thingys...

Kevanski

Too bad you didn't do the work yourself. You would have paid half of what you did. The battery and alternator are among the easiest to do on the Riviera. Not sure what the heat sink is.

When you're an old geezer, stuck in a small town, just moved there and don't know anyone, don't have automotive electrical skills, there's no space to work on your car, the mosquitos are as thick as soup, you're miles from the nearest city and you don't have a second vehicle, you will have no choice either!