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I have a problem with the firewall mounted circuit breaker on my 68 Vista Cruiser. It keeps tripping and resetting constantly. I have measured the amperage and it’s drawing 0.011 amps, trips goes to zero amps and in a few seconds resets. Voltage when set is 12.5. Does that indicate the circuit breaker is bad or a wiring issue? Your help is appreciated.
Last edited by oldsrock; May 22nd, 2023 at 03:42 PM.
Reason: Misspelling
My first question would be "when" does the circuit breaker trip? Can you try to diagnose when it trips? I'm not certain which power functions route through the circuit breaker on a 68 VC, but I'd attempt to determine when, which power device(s) trigger the circuit breaker to trip - e.g. power windows, power door locks, etc. I think those may be on a different circuit but I'm not sure what routes through the 68 VC circuit breaker. Start with all power options in the OFF position (everything - even if they're not routed through the circuit breaker), then one at a time, activate each function. I'm not sure I have the 68 PIM, if I do I'll look to see what routes through the circuit breaker. Most likely it is whatever routes through the circuit is drawing too many amps or as you suggested the circuit breaker could be bad. I do know I've taken them off the firewall and they're very easy to clean. It might be the case the terminals are exceedingly corroded and need a good cleaning.
My '71 CS convertible's power top was wired through the circuit breaker. The image below annotates which devices are wired through the circuit breaker - you have a power tailgate, power seats?
NOTE: This image is from the 1969 PIM (not the 1968 PIM). I can't speak to the fact '68 is same as '69. I'm sure if curmudgeon is viewing this thread he'll let me know.
The car has power window’s including the tailgate. No power seat. Breaker trips and resets with key on or off. I disconnected the power window relay. It has a constant 12v feed from the horn relay. One wire on the other side of the breaker goes through the firewall to the fuse box I think. I have the CSM and I’m not seeing the breaker in the wiring diagram. Does that help?
Thanks
I'm shooting from the hip here. NOTE: The 20A (fused) power relay ACC position on the front of the fuse panel/box. I'm not certain how each wire (power windows, SW window) is connected to that power relay. I'd begin an examination of the power relay perhaps? The wires in the back of the fuse box I assume are those independent wires (depending on accessory options e.g. power windows, SW rear window, cruise control, power antenna) which would feed onto the right-hand side of the circuit breaker mounted on the fire wall - they would run through that grommet on the firewall). Frayed cable, loose connection, bad relay? Shooting from the hip, sorry.
The car has power window’s including the tailgate. No power seat. Breaker trips and resets with key on or off. I disconnected the power window relay. It has a constant 12v feed from the horn relay. One wire on the other side of the breaker goes through the firewall to the fuse box I think. I have the CSM and I’m not seeing the breaker in the wiring diagram. Does that help?
Thanks
The power window wiring is in the Fisher Body Manual, not the CSM. The relay is just an isolation relay that closes when the key is in the RUN or ACC positions. This was done to avoid having to carry that 30A circuit through the ignition switch contacts. Check for a worn wire in the pigtail to the rear window where it flexes when you open the tailgate.
Thank you for the replies, I'll take a look at the tailgate wiring (if I can get the window down!)
The breaker is tripping without attempting to activate any switches, car is just sitting there not running. As soon as battery is connected the clicking begins.
What I'm not understanding is that a 30 A breaker is tripping under a 0.011 A load. The meter seems to have enough time to stabilize so I am tending to believe that number.
What am I missing here?
Thank you for the replies, I'll take a look at the tailgate wiring (if I can get the window down!)
The breaker is tripping without attempting to activate any switches, car is just sitting there not running. As soon as battery is connected the clicking begins.
What I'm not understanding is that a 30 A breaker is tripping under a 0.011 A load. The meter seems to have enough time to stabilize so I am tending to believe that number.
What am I missing here?
I agree regarding amp draw 0.011A is insignificant. Clean the circuit breaker or R&R the breaker.
Just throwing this one there folks, dyslexia bites sometimes trying to comprehend written stuff, but I had a similar problem on our Vista Cruiser (1972) years ago, and it turned out to be the rear window switch where the key goes not fully returning to a neutral position with the key released, thus it was keeping an up command to the back window motor constantly, thus tripping the relay off and on, torture to my ears. When I put the window down with the key, that annoyance went away! Putting it back up with the key in the back window made the darn thing start clicking non-stop again! But, when using the inside switch on the instrument panel, no problems. On a hunch I removed, and took apart that rear switch (no fun at all) and cleaned the suspected culprit. The annoying clicking went away. Check both your switches, who knows, this could be it. BTW, the rear switch with the key always gets power, the one on the instrument panel is a keyed on/off by the ignition. Hope this rambling on helps out!
Just throwing this one there folks, dyslexia bites sometimes trying to comprehend written stuff, but I had a similar problem on our Vista Cruiser (1972) years ago, and it turned out to be the rear window switch where the key goes not fully returning to a neutral position with the key released, thus it was keeping an up command to the back window motor constantly, thus tripping the relay off and on, torture to my ears. When I put the window down with the key, that annoyance went away! Putting it back up with the key in the back window made the darn thing start clicking non-stop again! But, when using the inside switch on the instrument panel, no problems. On a hunch I removed, and took apart that rear switch (no fun at all) and cleaned the suspected culprit. The annoying clicking went away. Check both your switches, who knows, this could be it. BTW, the rear switch with the key always gets power, the one on the instrument panel is a keyed on/off by the ignition. Hope this rambling on helps out!
That’s a great place to start considering I just changed out the breaker and the problem persists. I will give that a look and come back with the results. Thank you for the suggestion.
Hello,
I'm back to / still attempting to fix the problem that manifests itself as a tripping circuit breaker. What I have found is that the fusible link wire connected at the horn relay junction block is grounded. After disconnecting the fusible link wire from the junction block I have continuity to the negative post on the battery. With the fusible link wire connected to the junction block, if I unplug the two connectors in the photos below the breaker stops tripping. The orange/black stripe wires in both connectors labeled '1' in the photos are also grounded. The power windows, headlights, and accessory position of the ignition switch function normally with those disconnected. I know these connectors are related to the power tailgate window.. It's pretty hard to get to anything under the dash on a car with A/C plus an 8 track in the way. Would anyone have a suggestion on an easier place to start or do I just have to take the dash apart to find and trace every circuit connected to the fusible link wire, which is pretty much everything! .
I did look into Norms suggestion and no dice. At this point the rear window will not go up or down even when connected, Last May I did manage to bring it down about an inch at a time with the breaker tripping so I could open the tailgate. Now noting. This is stopping me from getting to the key switch.
Thanks for any ideas you might have and no I did not put that Scotchlok in there!
Connector 1 Orange Black Stripe wire from behind fuse box Connector 1 Orange Black stripe wire from behind fusebox
Save yourself enormous headaches troubleshooting this issue. It is essential you review/follow information contained in the 'Body by Fisher1968 Service Manual'. I own the Body by Fisher 1971 Service Manual which is useless in troubleshooting a 1968 since there exists significant differences between 1968 & 1969-1972 VC models. Here (below) is an exceptional price for a 1968 Body by Fisher Service Manual which contains exceptional diagnostics/checking/troubleshooting procedures complete w/ wiring diagrams for each circuit of the tailgate. There is no substitution for an original Body by Fisher Service Manual - you need this manual.
Thanks for the response. I do have all the relevant factory manuals, CSM, PIM and Fisher Body for the '68. I had forgotten that I disconnected a relay while trying to figure this out and the tailgate window is now working. Circuit breaker still tripping. I believe the root cause of the breaker tripping is the short in the fusible link wire. I removed the forward harness connector to the fuse panel on the firewall and located the terminal for fusible link wire. The wire is not shorted to ground on the engine side but the corresponding terminal on the fuse panel side of the engine compartment is shorted to ground. Looks like the issue is somewhere from the fuse panel to the back. There is a three way junction in this circuit shown in the CSM wiring diagram. Could someone tell me where to look for this in the car?
Thank you
Sounds like you're making progress - baby steps - yet, trending in a positive direction. I don't have the bandwidth (today) to provide any additional advice regarding specific location of the 3-way connector/splice. Easy for me to say it shouldn't be too difficult to determine its location other than to suggest it's a RED wire w/ three very distinct and independent routes. Turning the wiring diagram for easier viewing. Good Luck.
BTW, did you follow that one area of the Fisher Body Service Manual which (as I recall) specifically troubleshoots a breaker tripping? Just a suggestion to re-evaluate the troubleshooting chart.
Yes I did see the circuit breaker trouble shooting procedure in the power window section of the Fisher manual. The breaker is shorted because the fusible link wire is shorted and that connects to the horn relay along with the accessory feed wire running to the breaker, I pulled the tailgate switch and as expected the power feed to the switch is grounded. I have to believe these two shorts are related but just not sure what to go after first. I’m thinking I go after the tailgate circuit first as that may easier than getting into the instrument panel.
May 22nd, 2023, 03:41 PM
