[Dr_Solstice]

I just picked up an 07 base model 5speed and my backup lights aren't working. I've tried replacing bulbs and that's not it. I checked fuse 46 and it's good. I bought a replacement backup switch and am about to replace that. One question though: I pulled fuse 46 and when I put a meter across the terminals, with the key on and in reverse gear, I get 0V across the terminals. Would that be the case if the backup switch is faulty, of does 12V go across the fuse then to the switch and subsequently to the backup lamps?

Thanks.
Dr_S

 

[JohnWR]

I just picked up an 07 base model 5speed and my backup lights aren't working. I've tried replacing bulbs and that's not it. I checked fuse 46 and it's good. I bought a replacement backup switch and am about to replace that. One question though: I pulled fuse 46 and when I put a meter across the terminals, with the key on and in reverse gear, I get 0V across the terminals. Would that be the case if the backup switch is faulty, of does 12V go across the fuse then to the switch and subsequently to the backup lamps?

Thanks.
Dr_S

Manual or automatic transmission?

Assuming manual, the fuse should have power whenever the car is powered.

 

[Dr_Solstice]

Yes, it's a 5speed Manual- car power on, nothing across the fuse.

In the middle of trying to get the closeout floor panel out to get to the switch on the transmission without disconnecting the exhaust. There is one bolt that is really hard to access.

Dr_S

 

[Dr_Solstice]

So I verified there is power coming from the fuse box. Going to need to get the car on a lift to change out the switch.

Dr_S

 

[TomatoSoup]

Before you tear your car apart replacing the switch, you might want to check the wiring at the front of the car(Iin case it's a fault further back). The wires go via the passenger kick panel. Check the light green wires... photos here: (1) Backup Camera In Rear View Mirror Install | Page 7 | Saturn Sky Forum (skyroadster.com)

 

[Dr_Solstice]

I opened up the harness yesterday but ran out of time before I could do anymore. I say there were several light green wires but wasn't 100% sure which one was the backup wire. I'd rather only cut one wire if I have to. Any advice on the nearest connector I could pull to check for 12v along that wire?

Dr_S

 

[TomatoSoup]

As I recall, there were only two light green wires. Just use a dressmaker's pin to pierce the insulation and test both. The insulation will self-heal enough afterwards.

 

[Dr_Solstice]

I verified that the there is continuity from the harness under the passenger door sill to both backup lights. Looks like I'll be headed to a shop to get the car on a lift for the backup switch.

 

[Dr_Solstice]

Alright electric gurus: backup switch replaced and still no lights. Does anyone have any photos of the path from the fuse box to the backup switch and then from the switch to the passenger side wiring harness? Again, fuse is good and 12v there. Also continuity verified from passenger side harness to lights.

Thx.

 

[JohnWR]

Alright electric gurus: backup switch replaced and still no lights. Does anyone have any photos of the path from the fuse box to the backup switch and then from the switch to the passenger side wiring harness? Again, fuse is good and 12v there. Also continuity verified from passenger side harness to lights.

Thx.

Did you verify power at the switch? Did you verify power after the switch with the transmission in reverse?

Checking across the switch will not work, you have to check each terminal to ground.

 

[Dr_Solstice]

Unfortunately, they did not check for 12v coming to the switch. I can verify there is 12v at the fuse and also continuity at least from the wiring harness back to the lights. My next steps are to see if there are any wire breaks or issues from the fuse box to the switch or from the switch to the passenger side harness. I have not taken the passenger side kick panel off to trace the harness closer to the switch. I am particularly interested if anyone can verify where the wiring for the switch passes to the underside of the car and then returns to the passenger side harness. Worse case I can add a helper wire to bypass the issue. I have some wiring diagrams, but the manuals don't show enough detail on the harness routing.

Thanks

 

[Dr_Solstice]

After tracking down more diagrams, I think I have what I need now.

Thx

 

[Dr_Solstice]

Well, after lots of troubleshooting, I've isolated my backup light woes. Here is what I know:

There is switched 12V leaving the engine fusebox on the Pink wire from connector C1
There is continuity from the Light Green wire returning to C1 at the fusebox and leaving the fusebox at connectoir C2 all the way to the backup lamps.
(thus there are no broken blades or traces in the fusebox).
The backup switch was replaced recently.

As shown in the attachment there is a break in continuity somewhere between the 12V going to the backup switch and the returned 12V when the switch closes to and from C2. Of course I don't want to replace the entire wiring harness, so I would think a jumper wire would solve my problem.

Short of taking it back to the shop to have it put up on the lift again for them to run the wire, is there any place where the wire going to the backup switch is accessible through the transmission tunnel?

Any wisdom is appreaciated.

DrS

 

[JohnWR]

How confident are you that the switch is being actuated in reverse?

 

[Dr_Solstice]

I don't know for sure without getting under and accessing the switch at this point. Any tests I do at the wires leaving the fuse box would either point to a bad wire, bad switch, or a switch not getting actuated. I'd have to check continuity across the switch in and out of reverse to know for sure. So I can add that to the unknowns.

A reputable shop replaced the switch last week. I believe it was installed correctly.

I do find it difficult to think that the switch is not getting actuated, If there was some reason that was the case then I would expect something more sinister going on in the transmission, and I've rarely heard of that happening. That being said I can't rule it out.

DrS

 

[JohnWR]

Let me run through some points to verify that I know where you are.

With the car powered and the transmission in reverse:

• 12V is present at connector X1 pin A10 (Pink Wire)
• 12V is not present at connector X1 pin C4 (Lt Green Wire)

With the car not powered:

• There is continuity between connector X1 pin C4 (Lt Green Wire) and chassis ground (There will be resistance from the backup lamp)

 

[Dr_Solstice]

On my diagrams it C1 instead of X1, but yes, the A10 Pink Wire has 12V and 12V is NOT present at C4 when car is powered (ignition on) and the shifter is in reverse,

I verified continuity across C1-C4 and C2-E6.

With the ignition off, I connected C2-E6 to the +battery terminal and the backup lights were both activated.

DrS

 

[JohnWR]

On my diagrams it C1 instead of X1, but yes, the A10 Pink Wire has 12V and 12V is NOT present at C4 when car is powered (ignition on) and the shifter is in reverse,

I verified continuity across C1-C4 and C2-E6.

With the ignition off, I connected C2-E6 to the +battery terminal and the backup lights were both activated.

DrS

I do not see any way forward other than to get back under the car.

 

[Dr_Solstice]

I appreciate the reply.

I was hoping that there was some location where the wires going to the switch might be accessed (some secret access panel on the shifter tunnel). These cars are so rare, there aren't many people in my area who have the experience with one, so I've tried to troubleshoot as much as I can, and check the lowest hanging fruit. One way or another, I'll probably get the shop to splice in a couple of jumper wires and I can splice the one at A10 or C4 that fixes the issue.

Just from experience, the removal of the closeout panel under the transmission is a tough job due to several of the bolts being partially or completely obstructed by the exhaust. The switch connector then is up high on the transmission near the top of the tunnel, so its doable, but you definitely need to have the car securely up off the ground and plenty of room to work.

 

[JohnWR]

I appreciate the reply.

I was hoping that there was some location where the wires going to the switch might be accessed (some secret access panel on the shifter tunnel). These cars are so rare, there aren't many people in my area who have the experience with one, so I've tried to troubleshoot as much as I can, and check the lowest hanging fruit. One way or another, I'll probably get the shop to splice in a couple of jumper wires and I can splice the one at A10 or C4 that fixes the issue.

Just from experience, the removal of the closeout panel under the transmission is a tough job due to several of the bolts being partially or completely obstructed by the exhaust. The switch connector then is up high on the transmission near the top of the tunnel, so its doable, but you definitely need to have the car securely up off the ground and plenty of room to work.

I have not seen a panel in the transmission tunnel and have not seen one referenced.

Given that the switch wires use the same fuse block connector as the cooling fan, starter relay, AC compressor clutch, brake booster vacuum pump (if fitted), etc, I think it is safe to say that it runs through the engine bay and along the top of the transmission. You could examine that cable routing to see if anything is damaged. I haven't looked for this wire specifically, but it should run down over the top of the bellhousing.

I know that @HHGadget recently had his transmission out, so he should have some insight about the routing of the cable to the back-up lamp switch.

Does anything else not work? Do you know any of the history of the car? That wiring is fairly protected, and it seems unlikely that only one circuit would be damaged.