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Convertible top on my 67 Cutlass 442 and checking everything prior to putting it to bed for the winter I found the top went down fine and back up fine so I tried it again and it went down 2/3rds of the way then stopped. The top would then not go up or down. I checked around both rear wheels for leaks as I had a 68 chevelle that when that happened a cylinder was leaking but no leaks seen at wheels then looked in trunk for leak at pump and no leaks. Went back to switch and it worked and top went down and then about halfway up then quit again. Nothing! So I sat for a minute and then the switch worked fine. so I closed the top and once again here on the forum to see if anyone has had the same issues. It had been about 6 months from the last time I used the top switch. My thinking is switch is bad and gets hot therefore quits and after cooling down will work again. but the pump could be doing the same thing. any ideas, thanks Mike
You are likely tripping the circuit breaker on the firewall. It sounds like the system is drawing too much current for some reason. This could be a bad motor, bad wiring, bad switch, or a combination. It could also be a bad cicuit breaker or loose connections. I would start by checking/ cleaning all of the connections including the ground connection at the motor, connections at the circuit breaker, and all of the plug in connections throughout. If these are OK, the next step would be to see what current the system is actually drawing with an ammeter.
I don't know if my reasoning is applicable to your '67; but, the issue w/ convertible tops of select years (1971 I know because I've reviewed this) is there is no relay itself for the convertible top by & of itself. The current (and it can be all 40 amps) runs directly through the switch. That's an A$$LOAD of current (HEAT) piping through a switch which I believe is the primary reason these convertible switches often require replacement - heat kills. If you have (I suspect you do have) a circuit breaker in that circuit (probably on the firewall), it's possible you're exceeding the amperage load of the circuit breaker. It is (or should be at least) a circuit breaker which automagically resets after it cools. Might this be the issue? Not sure. Others will have additional insight. If you need a new switch, I can make a recommendation but the next time it happens, you might check the circuit is open (overheated).
When the top stopped moving, could you hear the pump running or not?
Pump running and top not moving is a hydraulic issue.
Pump not running is an electrical issue.
Unfortunately, I don't have an official Oldsmobile document/diagram of the 1967 circuit breaker, but I believe the same circuit breaker is used from 1967-1971 (based solely on several Internet searches); therefore, my diagrams below may or may not be appropriate.
Performing several searches does yield the same type circuit breaker used on my 1971 CS convertible as is supposedly used on the 1967 convertible. Location of the circuit breaker on the 1971 A-Body convertible is on the firewall behind the brake booster/windshield wiper motor. Good Luck. You might remove the breaker and clean 70 years of oxidation/corrosion/soot, etc. from the posts, etc.?
FWIW, the top on my '72 CS does the same thing going up - it gets all the way up to where I can stop it to latch one side or the other, but when I go to bump it again to latch the other side, there's no power to the switch for about a minute before it comes back.
...and that's with all newer wiring (i.e. all harnesses replaced throughout the whole car), circuit breaker, switch and pump equipment from when I replaced everything about 5 or so years back, so not a case of aging components.
The 72's have the plug-in circuit breaker which mounts to the fuse box amidst all the other fuses. I've even tried a few different CB's to rule out anything bad in that regard - all performed the same way.
Last edited by 70sgeek; December 18th, 2023 at 03:49 PM.
FWIW, the top on my '72 CS does the same thing going up - it gets all the way up to where I can stop it to latch one side or the other, but when I go to bump it again to latch the other side, there's no power to the switch for about a minute before it comes back.
...and that's with all newer wiring (i.e. all harnesses replaced throughout the whole car), circuit breaker, switch and pump equipment from when I replaced everything about 5 or so years back, so not a case of aging components.
The 72's have the plug-in circuit breaker which mounts to the fuse box amidst all the other fuses. I've even tried a few different CB's to rule out anything bad in that regard - all performed the same way.
What would be great information is to diagnose where (why) there is no power to the switch. You state "no power to the switch for about a minute before it comes back". Did you actually validate via a circuit/test light there is no power to the switch (or are you simply stating the switch didn't work so you assume there's no power to the switch?); or, did you test the power side of the circuity w/ a VOM/DMM to validate there was no power to the switch? I'd be interested to know if there is/was no power from the circuit breaker during each of these "about a minute" scenarios. This would help to determine if the circuit breaker was actually "working" - i.e. the circuit breaker "tripped" (e.g. didn't provide power because it was overheated), but then reset itself (after a brief cool down).
At least for my issue, it appears to be the circuit breaker tripping, thus cutting power to the switch until it resets (which typically occurs within a minute of the trip event). My interpretation is the amperage draw to raise the top is simply exceeding the breaker capacity causing it to trip.
My top frame was previously restored (via a prior owner probably sometime in the 90's or so) - it's mechanically straight, clean and not indicatively binding anywhere that I can tell, so not seeming to me to be a source of issue in that regard.
I do think however, replacement (i.e. aftermarket) circuit breakers may not be as good as the OEM units these convertibles came with and maybe that's the source of my particular issue - in high school my friend's parents had a beater-condition '70 CS convertible and worn out as that car was, it never had a breaker trip issue when raising/lowering the top.
Last edited by 70sgeek; December 19th, 2023 at 07:10 AM.
Most don't own a DMM capable of measuring amperage. I have a clamp amp meter which I can use either the clamp or probes. But, with that said, it's highly likely the amperage is being exceeded through the circuit breaker. Not surprisingly, many posts/threads have issues w/ the top switch itself failing when under continued usage over the years simply because of the heavy amperage load (heat). I think there are two primary contributing factors: (1) The ground system would be my first area to address - the amperage will sky rocket if the electric circuit is met with increased resistance from faulty ground connections - that includes the contact points, end terminals & wires themselves. Increased resistance increases amperage draw which in turn increases heat which increases wear & tear of the system; (2) Points of contact to include the top switch pins themselves - they get oxidized increasing resistance, the top switch installation & its ground connection. These connections need to be rock solid - any slop (looseness) in the connections is a source of increased resistance - you cannot pass current through air. I've changed these top switches, they're not easy, but they're not the most difficult. But, those connections need to be rock solid.
I believe you should have (3 wires) at the power top switch: ORANGE power wire from circuit breaker, a PURPLE (top DOWN cycle) wire & a GRAY (top UP cycle) wire from the top switch to the top motor. The wiring should be located in the Fisher Body Service Manual.
got all the stuff done so I could try and find the source of the issue. And I did. thanks to all cause I did find the breaker and the posts were rusted along with the nuts holding them in place. I removed the breaker and wire brushed the posts and replaced the nuts and star washers, buttoned it up and tested the top. Went up and down 4 times in a row and NO issues. Waited 30 minutes and again tested 3 times and no problems. Glad I did not have to go after the switch. Thanks to all once again. You guys are GREAT!
December 17th, 2023, 12:42 PM
