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Relay in 69 Cutlass plucking sound every 4 seconds
Hey folks. New here. Recently got a 69 Cutlass and am in the process of learning its idiosyncrasies—what works, what doesn’t, what needs attention. After a drive this morning there appeared a noise coming from the blower relay on the firewall, a metal plucking sound every 4 seconds. I hadn’t noticed until I shut the car off when unfortunately, the sound continues and wouldn’t stop. The previous owner had installed a battery cutoff so I assume there are drain issues, though I haven’t had an issue yet. The blower and horn work fine and both the 3-prong and single prong connectors are in place and look AOK. Any thoughts on what’s causing this pinging noise? Thanks. I’m sure I’ll be posting again soon.
You need to isolate the noise to a component. At that point we can give you a direction. Welcome to the site, post a formal intro in the Newbie forum when you get a chance.
Well, of course, the next step would be to disconnect the connectors on that relay and see whether the sound stops.
If so, then you need to put a test light between each terminal and ground and see whether there is any current flowing with the ignition off - there should be current all the time from the heavy wire that goes to the battery, and none from any of the other wires.
My guess is that it isn't really coming from that relay.
Thanks guys. I'm on the idiot end of electrical issues, and other than finding that the horn and blower motor connect to that relay, I'm not sure what else does. Pulling the single prong off (black wire) doesn't stop the sound, and though the relay looks new and there's no corrosion, the 3-prong (green, purple and thick black wires) is stuck and I want to unscrew the relay from the firewall as the brake booster is in the way. What are the 3 components on that prong? It does have AC though it's not hooked up, and the person who originally bought the car apparently didn't want to pony up for a clock—just an untouched clock face. The sound really does seem like it's coming from the relay, and I can feel slight movement when the sound clicks. Thanks folks.
Of the three remaining wires, the heavy purple wire goes to power the blower motor, the blue wire brings power in from the resistor block for the 3 low speeds, and the black/orange wire is the relay trigger, which clicks the relay to send power directly from the battery for High - this should only be hot when the A/C or heat is On, the blower switch is set to High, and the ignition switch is On.
Well you were of course correct. The sound isn't coming from the firewall relay, but likely just on the other side of the firewall near where the relay attaches. This is as best I can pinpoint, and listening inside around the steering column didn't pinpoint the sound. When I was disconnecting the relay terminals only to find that the ticking continued, I noticed that the secondary wire from the battery's positive cable would twitch slightly with each tick, and that the wire was getting hot near the connection to the main cable. Again, this happens whether the car is on or off, so I've kept the battery disconnected. Starts up just fine. Thoughts? Much appreciated folks.
The only thing I know of that might make a noise like that would be the clock, if it wasn't working well.
I think your only choice is to crawl under there with a flashlight and maybe a mechanic's stethoscope and poke around.
The source shouldn't be hard to find.
Could it be a circuit breaker tripping and resetting?
Typically there is one for the power windows and the power top (combined, if I'm not mistaken, which may depend on the year), and another built into the headlight switch.
Neither should be tripping unless the associated equipment is in use (though a short circuit in that line would cause repeated tripping, it would also cause the equipment itself not to function).
Just a few inches south of where I was looking—the convertible top circuit breaker. Winner winner, chicken dinner. Though now I have to figure out where the short is. And the noise repeats whether the engine is running or car is off. Thanks guys.
The top switch/motor is powered off the battery so the top can be raised or lowered without turning the key. It is possible there is not actually a short but your switch is stuck in either the up or down position. It is spring loaded so it should be in the center position when not in use.
The top switch in the car returns to OFF automatically and has to be toggled forward and back and held when putting the top up and down. I've only been able to raise or lower the top with the key in the ignition, and the circuit breaker pings continuously, even if the key is in my pocket. Is there a common place for shorts?
Glad you have found the noise. Now find the short. Check your wire diagram. I seem to think that breaker is for 2 circuits, but not sure about your year and model.
Good question. Since the original buyer didn't even spring for a clock and it came with the 2-barrel, I'm thinking there wasn't ever power-anything. Still has the bench and manual adjustment lever.
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I've only been able to raise or lower the top with the key in the ignition
That is different than my '71. I don't know if '69 is supposed to be the same or not, but I would guess yes. Perhaps someone has a '69 wiring diagram and can confirm how it's supposed to be.
Does it have a power antenna? If so then there is a power relay in the left door jamb behind the kick panel. Pain in the donkey to get at because you must loosen the park brake mechanism to remove the kick panel to get at the relay and then the fun begins! The cct breaker feeds that pwr relay in the door jamb. Another possibility is that someone installed a pwr relay to prevent the top from operating without the key on.
I think maybe the latter, that it may have been changed from the no-key required to operate since the key has to be turned for the top motor to receive juice. Again, power-nothing on this car—screw on/off antenna, which is fine by me. And thankfully, from the sound of it, I won't be dealing with a relay in the door jamb. As for the 72 convertible I drove daily for 17+ years, the top never worked and I had no problem stepping on the back seat and hoisting the top over me. Quite a bit faster process than the hydraulic motor actually, but I do want to keep this power top in good repair.
I don't know when they changed, but my 98 requires the key on for the top. The key powers up the relay in the kick panel and the juice from the breaker then supplies power to the windows, door, antenna and top switches. If I recall correctly. I remember being confused when they all failed at the same time. I could not find the breaker and relay in the CSM diagram, but in the body manual.
(or my mind is slipping again)
OK. Here's the scoop. The key IS required to operate my top, though the (a) previous owner installed their own toggle switch. That said, problem found, and it lay with said top switch. One of the wires connected to the switch had a single strand gone rogue which had actually fused to the underside of the dash, causing the breaker to repeatedly reset. A single strand. Man I hate electrical issues.
Glad you found it. I would be cautious about a aftermarket switch. Some switches are not rated enough and go bad faster. I replaced mine with a Cole-Hearsee or Eclin rated at least 30 amps. Some aftermarket cheap switches are junk.
Yeah, I don't trust too much on the car in terms of what's been done to it. But if complete reliability were my main concern, I wouldn't have jumped back into the waters, and damn if I don't feel like a king again driving "my father's Oldsmobile." My son, Charley, digs HIS father's Oldsmobile.
One of the wires connected to the switch had a single strand gone rogue which had actually fused to the underside of the dash, causing the breaker to repeatedly reset.
November 13th, 2016, 02:05 PM
