Instrument Cluster and Back up lights not working

[sjrobinson]

This is for a 98 Plymouth Grand Voyager 3.0L

The car has been neglected and I’m trying to get it to pass inspection. One of the things was the back up switch. I tested and replaced it and the back up lights worked fine. But then the battery died and I decided to leave it disconnected for a few days while I was working on other repairs.

I replace the valve cover gaskets (where I had to disconnect a 7 wire connector) and then connect everything back again. I go to jump start the car and the gauge cluster does not move or light up and the back up switch is not working. All the other lights work and the cluster with the system lights (CEL, Brake, Oil, etc.) right about the gauge cluster still lights up. The car starts up fine.

I checked the gauge fuse and it was fine but I swapped it with a good known fuse. The back up switch doesn’t have a fuse and it is still working when I do a continuity test.

Are the two things related by a connector or relay? Perhaps a connection at the ignition switch?

Thanks

Topic

[college man]

Check the connector or connectors that were unplugged.
Try and unplug and plug them in a few times. see if it
restores the cluster. here is a link for a wiring diagram.

http://www.bbbind.com/tech_database.html

[Kevin Criswell]

this might help some

Attachments:

• backupcircutgrandvoyager.pdf
• insturmentclustergrandvoyager.pdf

[sjrobinson]

I used the BBB Industries link (forgot about that site, I had it bookmarked) and found an overall power distribution diagram. I also looked at the other two links. I’m used to hondas so even the schematics for GM are a bit different to read.

Is the park/neutral switch the same as the back up switch?

What I’m seeing is that both of them meet at the junction block but im having difficulty finding a physical location or connector. Any of you guys see what could relate?

[sjrobinson]

Page 618 of
http://www.scribd.com/fullscreen/60464286?access_key=key-tj1xnmohbf9ucug3ocj&allow_share=true&view_mode=scroll

I see the back up switch goes to C2 and the instrument cluster goes to C4. I cant find anything related and there arent any other things that done work… but it could be the wiring to the lights themselves…

The the chime when the key is in the ignition and the door is open is hit or miss if that helps. This is a base model so there are almost no extra electrical accessories.

Update:

Page 819 I see that the back up lights run into nothing but the switch. The brake lights work, its just the back up lights that aren’t responding. But they did function when I first replaced the bad switch. The only thing I touched was a connector under the hood that was reconnected. I would like to see a central issue since both the gauge cluster and back up lights fail at the same time but am not sure if it’s a coincidence.

[Kevin Criswell]

[quote=”sjrobinson” post=75841]
Is the park/neutral switch the same as the back up switch?

What I’m seeing is that both of them meet at the junction block but im having difficulty finding a physical location or connector. Any of you guys see what could relate?[/quote]

Yes the park/neutral switch also handles the back up lights.

I can’t see a common point either. What might be best is to pretend that both problems are NOT caused by the same issue and tackle each one at a time. Sometimes two unrelated components will have issues at the same time making you think that they are related.

[sjrobinson]

Yeah I will have to go with that. But the event of the battery dying and having it removed for a few days may be related.

I’d say a surge in the system when I jump started it would blow a few fuses but there are no blown fuses I can find for those two devices.

What causes a back up switch to go bad in the first place?

[Kevin Criswell]

[quote=”sjrobinson” post=75864]Yeah I will have to go with that. But the event of the battery dying and having it removed for a few days may be related.

I’d say a surge in the system when I jump started it would blow a few fuses but there are no blown fuses I can find for those two devices.

What causes a back up switch to go bad in the first place?[/quote]

Inside of a “transmission position switch” or “park neutral switch” are moving carbon contacts that break and make circuits based on their position inside the switch. Since this is a mechanical electrical switch they wear out and corrosion or deposits on the contacts can make it where the circuit does not get completed.

[sjrobinson]

The back up switch just consists of three terminals to the connector and a fourth on the other side that connects to a piece of metal in the transmission that moves in front of it when the car is in reverse and completes a connection with the center terminal connected to the harness. The side two terminals conduct to each other.

I’m more familiar with other transmission switches that incorporate more than just the back up lights. This just is a switch solely dedicated to the back up lights I think. Perhaps other electrical actions associated with reverse.

I didn’t see the other switches in the circuit though. Would they influence the back up switch? From what I saw it was from the junction box to the switch and then to the back up lights, then ground. (ground is good since the brake lights work and the switch is new)

[Kevin Criswell]

Its an automatic, the switch also interrupts the starter circuit if the transmission is in anything other than neutral or park. They used to be called neutral safety switches.

Just follow the wiring diagram from fuse to switch than switch to bulb (with engine off, key on in reverse)

[Tom]

Start at the fuse box, with a voltage tester, and verify that there is 12V+ on both sides of the fuse for the reverse lights. From there, check at the switch on the transmission, and make sure you are getting voltage there. If the switch is getting voltage, put it in reverse, and verify that there is voltage coming out of the switch also. If that is the case, pull a reverse light bulb out, and verify that there is voltage and ground at it’s socket.

If all that checks out, replace the reverse light bulbs.

Now, repeat the process for the gauge cluster.

[sjrobinson]

Itll have to come down to a sequential process of elimination I guess.

I couldnt find a fuse labelled back up lights. But the FSM shows it leading to fuse 12. Ill check it all out and update this.

Thanks guys

[sjrobinson]

So I started tracing the wiring. Found that 12.5v was coming from the junction block to the switch but nothing to the light. Then I jumped the wires at the connector (since the switch is just a relay) and the lights worked. It seemed that the switch got fried…

I read the alternator output- it was 16.6v which suggested a bad voltage regulator. I disconnected one of the inputs to the junction block and then went to the instrument gauge. I turned the key and the cluster started up.

I then turn on the car and read the alternator voltage, it was 13.6v.

I have no idea what happened but something made the cluster work again. :blink:

But never look a gift horse in the mouth…

Now to address the other problems of this car,

Its burning coolant, I can smell it but theres no excessive smoke, just exhaust smoke that youd see in cooler weather. No coolant in the oil but before I replaced the coolant I did see a bit of oil at the fill cap.

[Tom]

Keep an eye on that alternator voltage. 16.6 is quite high. If there was oil at the radiator fill cap, that says bad things about the head gasket.

[sjrobinson]

Yeah. Originally I got a new battery for it and then later replaced the seized alternator. Then the battery died again. I thought it was a bad battery but maybe the alternator is faulty. While the voltage at the alternator was high, the battery always read about 13.5v with the car on.

Head gasket or cracked block/head. I’m gonna try some blue devil if my leak down test proves positive.

Make shift tester- gauge, tee and some hose? Monitor the system pressure and see what happens?

[Kevin Criswell]

sjrobinson

I would not bother with Bluedevil it is a patch fix at best and is known for only lasting a short time.

If you follow the comments the uploader later goes on to sell the truck as he had to blue devil it 2 more times when the problem came back.

I hate to say it and I am not trying to be rude saying it, but there is no chemical fix for a mechanical problem.

[Author]

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