87oldscutty

On my 1987 Cutlass the turn signals work but rather slow but when the headlights are on they do not work. I have replaced the bulbs and noticed when this happens the front corner lights do not come on. Also my dash light was very dim this morning and when my blinkers are on the check engine light flickers and charge light comes on every now and then. Could someone point me in the right direction.

jaunty75

After all that, how about a psychiatrist's couch?

Many electrical problems are due to poor grounds

87oldscutty

I did see a ground strap connected to the firewall but nothing else. Could that be it?

jaunty75

Heck yes! The other end should probably be connected to the engine.

87oldscutty

Ok I will try that. Thanks so much

jaunty75

Look for a bolt on the engine in the vicinity of the strap that isn't holding anything on. There should be a hole in each end of the strap for the attaching bolts to pass through. If the strap is broken, there might still be the other half hanging on that bolt.

87oldscutty

The ground strap looks intact. I seen a bolt on a bracket that appears to have no use could it go there? I'm new to this and trying to get this figured out

jaunty75

It certainly could go on that bolt. Hook it up and see. You can't have too many grounds. If you can get a good close-up, snap a photo of what you're looking at and post it here. Pictures are worth 1000 words at least.

joe_padavano

And this one DEFINITELY is a bad ground. It's not going to be the ground strap, however, it will be the grounds at the light sockets, more likely. Each socket either has a black ground wire that is held by a screw to the body structure or grounds through metal tabs in the socket that snap into the light fixture housing. If the ground is bad, the turn signal circuit grounds instead through the parking light circuit. The extra resistance in the second set of filaments is why the turn signals are slow. When you turn on the headlights (and thus the park lights) there is now +12V on the park light circuit and the turn signals can't use that ground path any more, which is why they don't work with the lights on.

87oldscutty

How would I track it down? Would grounding the corner lamps because that's the ones I'm having trouble with. I am gonna hook the ground strap back up too

jaunty75

It sounds like that would be the place to start. You'll have to check each socket and make sure the ground side really is grounded. A volt/ohmmeter would be very useful here.

Based on Joe's description, it sounds like your problem is with the turn signal circuit, so you'll at least want to check the ground at the socket of each light that flashes or is supposed to flash when the turn signal is activated.

87oldscutty

Ok thanks. I will try that

87oldscutty

Dumb question could the switch be bad

jaunty75

Anything is possible. So how did your examination of the turn signal bulb sockets go? Judging from this comment, I'm guessing you didn't find anything wrong.

87oldscutty

I tried grounding the lights that didn't help. Replaced the flasher nothing changed. I don't know what else to do

jaunty75

This is a bit confusing. What do you mean by "grounding the lights." There could be a dozen separate light bulbs that flash depending on the position of the turn signal switch.

The idea wasn't to ground the lights per se. The idea was to check the wiring at each socket in which a bulb that flashes when the turn signals are on is located, and make sure that the ground side of each one of these sockets is actually properly grounded. On a typical car, this could be, what, maybe 8, 10, or 12 sockets depending on how many bulbs actually flash in the rear of the car on each side and assuming the side lights are actually separate lights and not forward-facing lights that can also be seen from the side. The best way to do this, I think, is to take an ohm meter, touch one lead to the car's body near the socket and the other lead to the terminal in the socket that the ground side of the bulb connects to. You should get zero resistance.

This is by far, I think, the best way to check for a good ground as a complete visual inspection may be difficult without pulling apart the light assembly. You don't want to have to disassemble every light fixture on your car if you don't have to. Using the ohm meter, you will hopefully find one (or more) socket that isn't properly grounded, and you'll pull that fixture apart to locate the problem and correct it.

svnt442

With the charge light coming on I'd start with the basics and work my way down to the small stuff. Start with the battery connections. Make sure they are CLEAN and tight. Then move on to the other end of the battery cables and again make sure you have good connections there. The negative will be easier to get to as it should be bolted to either the front of the block or the alternator bracket. You will have to drop the starter to check the other end of the positive cable. I know...PITA, but with what you are describing it can't hurt.
Then you want to make sure all of the braided ground straps are connected to the engine as they should be. I think there are at least 2 and possibly more.
Then you can move down the electrical line and start checking the small wiring going to the lights, but I'd bet you find the issue in the large wiring somewhere.

MDchanic

Yeah, Question #1 for me would be, What voltage is your alternator putting out?

All of these problems could be caused by low voltage, and / or by dirty connections between the alternator and the battery, as well as the other things mentioned.

- Eric

jaunty75

Yes, the "basics" would certainly be things to check, and certainly alternator output and so forth are good to check, too. But the symptoms point most likely to a bad ground in the turn signal circuitry as Mr. P suggests. If it were me, I would start with what the symptoms point to and then broaden the search if that approach doesn't reveal the problem.

I mean, svnt442 is talking about dropping the starter. That's in a different league altogether from simply pulling out a light bulb and checking the socket for a good ground.

svnt442

That's because I doubt the issue it at the end point and more likely closer to the beginning of the charging system.
You must admit that on these older cars the charging/electrical systems are usually neglected pretty badly.

jaunty75

Yes, but with an ohm meter and 10 minutes, he can go through the entire set of turn signal bulb sockets and check for good grounds and do it without getting his hands dirty. Given the strong likelihood that this is the source of the problem in this particular instance, it certainly pays to try this first and then start crawling under the car and dropping starters.

Yes, old cars can have a myriad of electrical problems, and they're often difficult to pinpoint the source of. But in this particular case, the symptoms strongly suggest the source of the problem, so I would start there, especially given the fact that doing so is simple and fast, and if I end up not finding the problem after all, I haven't wasted any time.

svnt442

This is why I HATE electrical issues.

MDchanic

With a voltmeter and 30 seconds, he can see whether the alternator is charging at 14 volts or at 12.

- Eric

jaunty75

I hate them, too. They can be the most vexing type of problem you can have with a car.

But it's interesting how many times the problem ends up being a simple fix once you find it, and how satisfying it can be when you finally do solve it and your lights start working.

I had tough electrical problems with both of my old cars. In the case of my '67 Delta 88, when I first got the car, the taillights would go on whenever the ignition was in the ON position. Pulling out the headlight switch would turn the headlights on, but it had no effect on the taillights. I ultimately gave up looking for the cause and went on to other things. I solved it by accident one day when I removed the wire from the underhood light so I could remove the light and clean it up. As soon as I pulled the wire off of it, the taillights started working properly. I didn't notice this immediately as I didn't have the ignition on when I was working on the underhood light. But before I had the light cleaned up and reattached, I had occasion to take the car for a drive at night, and lo and behold, I noticed the now-properly-working taillights.

It turned out a prior owner had hooked the wrong wire to the underhood light, and the system was grounding through that connection. Very weird, and I still don't really understand how it all went down, but I was so glad to fix the problem.

I also had a taillight problem with my '73 Custom Cruiser, but this time the fuse would blow the moment you pulled out the headlight switch. There was obviously a short in a wire somewhere, but where? I couldn't check power to each taillight socket because there was no way to get power to them because the fuse would blow the moment any power was applied. So I had to resort to tracing the wiring for the taillight on each side, and I ultimately found that when the taillights and trim were removed and then reattached when the car was painted, one of the wires got pinched. The only way to find this was to take the system apart little by little and look.

I also had a problem with the power tailgate, which drops into the floor on these cars. It wouldn't budge no matter what. I removed the motor and determined that it was OK, but neither the dash switch nor the key switch at the rear would make it move. The power window worked fine.

I ultimately found that a relay in the wiring towards the front of the car was missing altogether, so that fixed the front switch problem, and I ultimately found that the rear key switch had not been properly reassembled when it was removed for the repainting. Once I had that back together properly, the key switch worked fine.

I have to say that, for the second problem, having the Fisher Body manual for 1973 was a godsend. It had detailed diagrams of the key switch area, without which I would never likely have figured out how to remove and disassemble it.

jaunty75

Yes, but even if it's 12 instead of 14, it's not likely to be the cause of the specific problem he's having with the turn signals. Remember, it's the turn signals that are exhibiting the peculiar symptoms here. Start there and and then broaden out if necessary.

svnt442

AND he stated that the charge light was coming on and that indicates low voltage in the entire system, not just the turn signals. That's why I advocated checking the big stuff first.

MDchanic

Au contraire.

His signals are slow (low voltage, either input or ground problem, or both), and
they don't work when the headlights are on (low voltage),
his dash lights are dim (low voltage), and
his ALT light comes on (low voltage).

I'd spend 30 seconds to check the voltage. If it's good, then proceed with the rest.

Basics first.

- Eric

jaunty75

Yes, he did, but I would START with the turn signals because electrical problems manifest themselves in unexpected ways, and fixing the turn signal problem might very well fix these other problems as well.

jaunty75

"Au contraire"

(I can be annoyingly French, too.)

All of those problems can be caused by a bad ground in the taillight circuit, and because of the specific symptom that the turn signals DO work when the headlights are off but DON'T work when they're on suggests that there is a ground problem there. Fix that, and all the other symptoms could very well disappear. If not, then continue to troubleshoot.

starfire

My money's on Eric and the alternator, but I think you guys scared off the OP with your bickering

87oldscutty

I didn't realize there were this many replies. I think I am going to start off by changing battery cables because the previous owner put a top post battery in it when it should be side post. The alternator is only putting out 12 volts when I checked it today and when you guys say use a ohm meter on the sockets what are the specs I should be looking for? I got this car as a project and looks like I am gonna have more of an electrical project than anything else haha

87oldscutty

also I was looking today for the wiring on my car for the side marker light (on driver side fender) and the bulb and wiring are mia and starting to think that could be my problem right there but I can not find the wires to fix it.

MDchanic

Bickering? We are having a highly refined and intellectual tête-à-tête.



The alternator should be putting out 13.5 to 14 volte.
12 volts means it's not charging.

Check your battery voltage with the car switched off and when you are cranking it to start and let us know the readings.



You should have 0Ω between the socket housings and ground, and 0Ω between the center contacts and the center contacts of any other sockets in the circuit (with all the bulbs removed).



I think we're getting to where we're going to need some pictures.

- Eric

starfire

I'm going to ask a stupid question here, but in the picture below are you looking for wiring and a bulb at the red arrow or the blue?

1987_oldsmobile_cutlass_supreme-pic-6479471427127325150_zps7da3e43f.jpeg



If you are looking for them at the red arrow you won't find them as that is just a reflector. The blue arrow points to the side/front marker light. I only ask because I once mistook the reflector for a side marker light (like my '68 has) on my '87 442. Then I realized the wrap around feature of the side/front marker light (doesn't really function as front marker light, but looks like it should).

87oldscutty

as for the marker light I am referring to the one with the red arrow. I thought so too and pulled the lense off and it has a hole in it and when I went to the passenger side I took the cover off there was a bulb. I will get some pictures tomorrow. MDchanic I checked the voltage at the battery with the car off was 12.16 to 12.24 volts. When you say you need pictures what are you needing pictures of so I can get the pics needed

starfire

Geez, you're like an old married couple...

starfire

It may have a hole in it, but it is not your side marker light. The blue arrow points to your side marker light. I need to thank you though, when I went out to double check I found that my drivers side side marker light is out. Need to get a new bulb put in tomorrow.

I don't know why your passenger side reflector would have a bulb in it. There would be no reason to have two front side marker lights. The bean counters at GM would have nixed that immediately. I am amazed the cars have a SML and a reflector.

You need to put your meter on your battery when the car is running. You should be seeing the 13.5 to 14 volts if your alt is working properly. The voltage on your battery is always going to read somewhere around 12 volts (unless it is somewhat discharged) when the car is off.

87oldscutty

the alternator probably is bad or weak. I am probably gonna replace it and put the right battery in it and cables too because it looks like a hack job in my opinion. since there shouldn't be a bulb I am back to square one. I told my wife I wanted a project and I guess I got what I wanted haha

MDchanic

A fully charged battery should read about 12.5V, so that's a bit low.
It's consistent with the alternator not charging well, which could be for a number of reasons, starting with bad connections (or bad ground connections).


I think Allan's got that covered, and he knows the actual body style in question, which is helpful.

Pretty much anything you ask about, a photo is helpful.

- Eric

87oldscutty

I will get some pictures tomorrow. I will also upload a video to youtube of it running with the voltage tester on the battery. how do I upload pictures on here?