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The instrument panel lights went out in my 69 Toronado. Only the back-lights for the speedometer, etc. - All other lights, interior and exterior, seem to be working properly. I'm thinking it's likely a fuse, but am not good at troubleshooting problems. I'm a good "parts replacer." Which fuse would this be, or is there something else that's a likely culprit?
or is there something else that's a likely culprit?
Have you verified that the problem isn't the rheostat on the headlight switch that dims the panel lights? Be sure the **** is all the way counterclockwise (without turning on the dome light). Try rotating the **** back and forth, as sometimes the rheostat wire corrodes.
Have you verified that the problem isn't the rheostat on the headlight switch that dims the panel lights? Be sure the **** is all the way counterclockwise (without turning on the dome light). Try rotating the **** back and forth, as sometimes the rheostat wire corrodes.
Thanks Joe! I have rotated the **** back a forth a number of times, but haven't done anything else to it. If the fuse doesn't do it, is that **** the likely culprit? Do I need to find a replacement for the whole thing, or is there another way to fix it?
Thanks Joe! I have rotated the **** back a forth a number of times, but haven't done anything else to it. If the fuse doesn't do it, is that **** the likely culprit? Do I need to find a replacement for the whole thing, or is there another way to fix it?
Thank you!
The panel illumination lights are ultimately fed from the headlight switch. The rheostat output is a green wire from the switch that runs back to the fuse panel and feeds that 4A fuse. The other side of that fuse feeds the IP connector. Use a voltmeter or test light to see if you have 12V on the 4A fuse at the panel when the headlight switch is on. If you do, the problem is between the fuse panel and the instrument panel. If not, then the problem is between the headlight switch and the 4A fuse.
No voltage coming through the headlight switch. What's my next move? Can I disassemble the switch and replace a single part, or do I need to source a complete switch?
No voltage coming through the headlight switch. What's my next move? Can I disassemble the switch and replace a single part, or do I need to source a complete switch?
I have not replaced a Toro headlight switch before, so I'll defer to someone who has. The headlight **** needs to come out first. Pull the **** to the Headlights On position (with the battery disconnected), then reach around and depress the release button on the switch as shown below. With the button pressed, pull the **** the rest of the way out of the switch. This allows you to unscrew the retainer, which frees the switch from the dash.
The headlight switch may be a special, with a vacuum switch attached (I don't know Toros either).
If so, the original is probably hard to find, but it should be possible to transplant parts from a new switch, if this is found to be necessary.
- Eric
It is and it does have a vacuum switch integrated. The photo I posted is a 68-73 Corvette switch, which looks amazingly like the drawing of the Toro switch in the CSM. Corvette specialty houses sell this switch for around $32.
The Corvette world has lots of posts about this headlight switch, including photos of how the top plate with the vacuum switch can come off and be swapped.
I got one of the Corvette switches. It seems like everything will work, but the vacuum ports are slightly larger than on the old switch and the hoses won't fit over them without splitting. Is there some type of adapter I can buy, or a recommended way of handling this problem?
I got one of the Corvette switches. It seems like everything will work, but the vacuum ports are slightly larger than on the old switch and the hoses won't fit over them without splitting. Is there some type of adapter I can buy, or a recommended way of handling this problem?
Good, so the next step is to check the voltage in the grey wire. Easiest will be at one of the sockets, but you can also intercept it as close to the fusebox as possible and stick a pin through it to probe it there.
With the **** in the full CCW position, it reads 0V. At the full CW position, it reads -12V.
How, exactly, are you testing this? The voltage out of the headlight switch should be batter voltage with the **** CCW and near zero with the **** CW. I would suggest using a test lamp, not a VOM, especially if that is not a high-impedance VOM. When connected to the fuse (and the other end of the test lamp grounded) the lamp should be bright at CCW and dim as you turn the **** the other way.
Sorry. My mistake. I am, indeed getting 0V at full CW and 11.5V at full CCW at the fuse, and I get 11.5V at the grey wire off of the headlight switch, as well. Still no light on the panels, though.
Sorry. My mistake. I am, indeed getting 0V at full CW and 11.5V at full CCW at the fuse, and I get 11.5V at the grey wire off of the headlight switch, as well. Still no light on the panels, though.
If you have power at the fuse, the problem is between the fuse and the instrument panel. There are several possible causes, though a loose pin on the IP connector would likely be high on my list.
Is this the grey wire that comes out of the ACCSY harness on the front of the fuse box on the lower righthand corner? If so, I am no getting any reading there. If not, which wire am I looking for?
If you have power at the fuse, the problem is between the fuse and the instrument panel. There are several possible causes, though a loose pin on the IP connector would likely be high on my list.
Thanks Joe. Which connector would that be? Up on the back of the panel? I can sort of see up there, but can't get to that area easily.
Thanks Joe. Which connector would that be? Up on the back of the panel? I can sort of see up there, but can't get to that area easily.
The IP lamps are fed by a grey wire that comes out of the back of the fuse panel, not the front. Apparently there is a splice in the wire behind the dash, as it feeds both sides of the instrument panel (with a separate connector for each) as well as the heater illumination. Given that, it is unlikely that multiple pins in multiple connectors failed simultaneously. There is definitely a problem with this feed wire from the fuse panel, however. Unfortunately, at this point you need to perform brute force circuit tracing.
The IP lamps are fed by a grey wire that comes out of the back of the fuse panel, not the front. Apparently there is a splice in the wire behind the dash, as it feeds both sides of the instrument panel (with a separate connector for each) as well as the heater illumination. Given that, it is unlikely that multiple pins in multiple connectors failed simultaneously. There is definitely a problem with this feed wire from the fuse panel, however. Unfortunately, at this point you need to perform brute force circuit tracing.
Thanks Joe. Just to clarify before I dig in. This would be the gray wire on the firewall side of the fuse box, not on the cab side?
Thanks Joe. Just to clarify before I dig in. This would be the gray wire on the firewall side of the fuse box, not on the cab side?
Yes, I called the firewall side the "BACK". This grey wire is integral to the harness coming out of the fuse panel. It is not one of the accessory wires that plug into the front.
You mentioned that you had the same voltage at both ends of the fuse, but did you check the voltage on the fuse contact? The contacts in the fuse box can and do corrode and prevent the voltage from leaving the fuse box even though it is passing through the fuse. If you find the contacts are corroded, you can remove the fuse and use a small wire brush to clean them up. Make sure you disconnect the battery before using a wire brush across the fuse box. No need for a light show until everything is cleaned up.
Thanks for the additional input, everyone. I have gotten the lights working again, however, they are extremely dim, even when turned all the way up. Any ideas?
Thanks so much to everyone who has contributed and continues to help!
... they are extremely dim, even when turned all the way up. Any ideas?
You've got resistance somewhere.
First guess is always the nichrome rheostat wire.
Next would be rust on the fuse clips (both the taillights fuse and the instrument lights fuse).
Next would be summed effects of various terminals and connections, including the connections at the horn relay lug.
Try jumping directly from the battery (+) to various points (fuse clip AFTER the inst. fuse, with fuse not installed, taillight power input of headlight switch, etc.).
Unfortunately, this can get annoying, but you WILL get it figured out and fixed.
July 27th, 2016, 09:13 AM
