[linderpat]

Both of my reverse lights are out. Do these lights require a special relay, or will a standard 53 or some other multiuse relay work? I'm not even sure it is a relay issue, but that seems like the best place to start.

[smiffypr]

Wiring varies according to model year, market, options (e.g. auto gearbox) so unless you give that information, you won't get the right answer.
Smiffy

[linderpat]

Sorry. it's a US spec 85 5 speed.

[smiffypr]

Fuse 12 supplies power to the switch on the gearbox, which connects to the lamps, no relay as it's a manual gearbox. Try the fuse.

[worf]

Thank goodness it is a manual. The reverse light circuit on the Autos is… baroque.

If it isn’t the fuse, report back.

Do you have (and can you use) a multimeter?

[linderpat]

I have a multimeter. What else should I check? TIA

[smiffypr]

With ignition on and gearbox in reverse: Check voltage at each side of the fuse, then each side of the switch on the gearbox, then at the lamp contacts.

[worf]

Check at the connector for the transaxle harness in the spare tire well first. This will tell you on which side is the problem.

I was planning on digging out the wiring diagrams after dinner.

Hang on…

blue and brown wires on a 4-pin connector that the diagrams indicate is 1/2-empty. There should be a plastic shroud over the electrics in the top right corner of the well.

Unplug the connector and probe the transaxle-side.

With the gear shift in any position other than reverse there should be no continuity between pins 3 and 4. In reverse, those two pins should have continuity.

If the above is not true the problem is the reverse switch or the stub harness that exits the spare tire well and goes to the switch on the transaxle.

If the above is true, the continue with smithyprs’s advice.

[linderpat]

Thanks guys. We’ll see how it goes.

[linderpat]

Also, I assume these checks are with the key in, ignition on, but car not running

[worf]

Also, I assume these checks are with the key in, ignition on, but car not running

my check requires nothing other than a battery in the multimeter (and it on and in continuity-check mode.)

[linderpat]

.......With the gear shift in any position other than reverse there should be no continuity between pins 3 and 4. In reverse, those two pins should have continuity.

If the above is not true the problem is the reverse switch or the stub harness that exits the spare tire well and goes to the switch on the transaxle.

..........

This is what I found - no continuity with trans in reverse or not in reverse. So a new switch is likely to rectify.

[Scott at Team Harco]

Or, it's in the harness.

[linderpat]

It could be, but honestly all of my harnesses are in pretty good shape. None are baked and brittle. So unlikely that the harness would be bad.

[Scott at Team Harco]

It could be, but honestly all of my harnesses are in pretty good shape. None are baked and brittle. So unlikely that the harness would be bad.

A resistance check of each wire would conclusively determine whether good, or bad.

[worf]

If the above is not true the problem is the reverse switch or the stub harness that exits the spare tire well and goes to the switch on the transaxle.

..........

This is what I found - no continuity with trans in reverse or not in reverse. So a new switch is likely to rectify.

Ok. So, first are you 100% certain that your test methodology was correct? You verified that the meter would register continuity on itself or some other wire? I always do this just to be certain. Right wires tested? On the correct connector?

Double-checking ‘cause the next steps are more involved.

You’ll need to get it up in the air. Liftbars, etc.

The switch is on the forward-left side of the transaxle. It’s the only electrical-looking think on the left side.

The harness end doesn’t have a plug for the switch. It’s just two pins soldered to the wires that plug into the switch: Don’t yank on it or you’ll break the wire at the solder joints to the pins. Instead…

Carefully, gently, pull back the dust boot on the switch and with some small needle-nose pliers, or big tweezers, etc., wiggle out each of the two pins from the switch.

At that point check continuity of each wire from the pin, back to the connector in the spare tire well. If you’ve got continuity then it probably is the switch (might still be intermittent wiring issues or just oxidation of pins) so, do my first-described test again but directly at the switch.

[linderpat]

Thanks Dave. Yes, defintly calibrated multimeter to make sure it was working properly. As to this next test, I do have the car on liftbars, and will look underneath at the switch. I tend to be a bull in a china shop though when it comes to fidly little soldered connectors, so this next part may be best handled by my indy next week when the car goes in for inspection. I already ordered the switch from Roger. I'll have to advise my indy about the washer/spacer to ensure the brake lights work properly. Rick had an issue and needed a spacer to make it work right.

[worf]

I'll have to advise my indy about the washer/spacer to ensure the brake lights work properly. Rick had an issue and needed a spacer to make it work right.

You lost me there.

[linderpat]

evidently there is a plunger that activates the reverse lights, and it can pop out too far unless a washer is used when mounting the spacer. Otherwise the reverse lights stay on. Saw that in a post on TOS by Rick. Maybe he'll chime in here and add more detail. Of course I could be totally wrong and misread the thread, especially since I haven't gotten under there to look at the switch.

[WyattsRide]

evidently there is a plunger that activates the reverse lights, and it can pop out too far unless a washer is used when mounting the spacer. Otherwise the reverse lights stay on. Saw that in a post on TOS by Rick. Maybe he'll chime in here and add more detail. Of course I could be totally wrong and misread the thread, especially since I haven't gotten under there to look at the switch.

I think you meant to say "when mounting the SWITCH"

My problem with my old switch was that the plunger rod (for a lack of a better term) seemed to be too long when fully screwing in the switch. The reverse lights would always be on. With a washer between the transaxle and switch it would be just enough to not let the plunger rod engage fully and the lights would stay off until the shifter was actually in reverse. This worked "most" of the time but was still finicky. Sometimes I would have to hold the shifter tighter in place for the lights to work. Sometimes not.
At my last inspection with our indy mechanic (Pete), the reverse lights didn't work for him and he ordered a new switch and did some magical adjustments. It works flawlessly now. Don't know what he did.
I would call him Ed.

[linderpat]

I ordered the part from Roger and the car goes to Pete next week for inspection. He can put it in then.

[linderpat]

Well I found the problem - very carefully pulled the boot back, as I was going o replace the switch with the new one I got from roger. The wires were broken off at the pins. The existing switch is probably fine. I'll have my indy fix it up this week when it goes in for inspection. Should be a lot easier to splice in new pins with the car on a proper lift.

The other frustrating project was my oil sender. My guage has been reading zero. I tested my sender and that seemed to be the problem. The harness from the sender to the 14 pin is fine. I ran 12 volts through it and the multimeter showed 12 volts. Put in new sender, hooked up the pins correctly, and still no joy. I think it might be in the pod, as it was wonky for awhile - sometimes working and sometimes not, before it died altogether. So I have more to do there.

[worf]

Should be a lot easier to splice in new resolder pins with the car on a proper lift.

FIFY

[worf]

Well I found the problem - very carefully pulled the boot back, as I was going o replace the switch with the new one I got from roger. The wires were broken off at the pins. The existing switch is probably fine.

Maybe. Maybe not. The act of pulling back the boot may have broken the solder joints. (i.e. Your indy should do the direct test on the existing switch and also resolder the pins to the wires in the harness. )

That harness is trivial to remove. The rework can be done at the bench.