Transmission issue? Gages quit in 5th...
 

Starting today, everytime i shift into 5th gear, my tach, fuel, and oil pressure gauges drop to zero, and all the warning lights are disfunctional. The clock still works though. Once i go down to fouth or any other gear, they come back on. Has anyone had a similar problem? To be even more specific, they all start to drop when i push the shifter to the right before i even actually push it up to go into fifth. Help! I have absolutely no idea what may be causing this.

I don't know how or why, but it's got to be related to the 5th gear / reverse switch on the transmission. It will be the switch with 4 wires running into it. 2 are for the useless 5th gear switch portion, and 2 are for the reverse switch, which turns your reverse lights on. Unplug the the 2 for the 5th gear switch and see if it still does it. Wire colors are in the FSM, but you can also unplug 2 and see if the reverse lights still come on when you shift into reverse. If they don't, it's the other two wires.

Update: The meter fuse was blown. So i replaced it with another 7.5 fuse, started it up, and all was fine. Sitting still, just goin through the gears, all cluster gauges and warning lights (brake only) would fail everytime i went into fifth gear. I still have working reverse lights. The fuse also blew as soon as I shifted into fifth. But wold come back again after going into every other gear. I dont think there is anything wrong behind the guages themselves, so im thinkin rotaryrocket88 is on point in saying that its a transmission related switch. Theres 4 back there i think, can anyone tell me which one to specifically look at? And why the hell would the meter fuse be constantly blowing? Grounding out somewhere? I just dont understand the link between fifth gear, the gauge cluster, and reverse lights, especially being that the reverse lights are still working properly. Thanks again for your input! Brian

The 5th gear/rev switch should be the one facing the rear of the car, that is directly over the transmission crossmember on the driver-side. There are only 2 switches on the transmission; the other only has 2 wires going to it, and is on the passenger-side. Figure out which two are for the 5th gear side of the switch and test continuity with a multimeter. One will be ground & should make the meter beep if you touch the other lead to the chassis. But the second wire will be power, and shouldn't beep if you touch the lead to the chassis again. If it does, you have a short somewhere down the line. That wire runs up the transmission tunnel towards the engine bay.

cool. i have a spare gearbox, and i looked at the switch. theres 2 red wires and 2 black wires. i havent gotten under the car yet cuz its been raining all day, so ill be doing that tomorrow. should the wires goin to the reverse lights be routed separately from the 5th gear switch for easy distinguishment? i just dont wanna get them all mixed up.

On the engine harness, the two wires for the 5th gear/overtop switch are black & black/blue. The reverse switch wires are red/green & black/yellow. This info is on page 50-116 of the S4 wiring diagrams.

Man this issue is killin me. Finally got under her today, found and cleaned everything up. All wires are secure, away from any part of the chassis, and all the wire wrap is strong and intact. Keep blowing the meter fuse in 5th, but yet the reverse lights still work. I dunno, are there any chances that the reverse/5th switch may need replaced?

Just unplug the two wires for the 5th gear switch. All it does is let the ECU activate the split air solenoid during 5th gear cruising, and keep the shift up light from coming on in 5th gear. It's not needed at all, and if your problem goes away with it unplugged, you'll know where the problem is.

i unplugged the 2 wires to the 5th switch and tried it out. and it worked. so i was all like rock on! well, then when i turned the ignition off and pulled the key out, the damn turbo timer stayed at 30 and i couldnt manually shut it off. i had to disconnect the battery to clear everything. once i did that, i figured there might be a tie in from the turbo timer, so i disconnected that, and now im back to square 1 of blowing fuses with the 5th switch pulgged in. im gonna go out now ant try to disconn both the 5th switch and the timer and see if it goes away. ill let you know in a few what happens.

just disconnect the Turbo timer.
That seems to be Related to the Issue.
I am thinking the Turbo timer is Wired wrong,and it effects your 5th gear switch somehow.
you already Disconnected the Switch,but the Timer Went Wierd,
so try to disconnect the timer(wiring,fully disconnect it,go back to Stock),but have the Switch on.

i see what youre saying, but with the switch on, it blows the meter fuse repeatedly. with it unplugged, the timer stays on. then with the timer completely unplugged, and the 5th switch plugged in, it blows the meter fuse again. this all happened at one shot. no warning, no intermittent faults. just like BOOM! and it all just went to shit on me. lol had the car for 2 months. but like i said, ima go unplug the 5th switch again along with the timer and see what happens.

Heres something new... With the meter fuse removed, not just blown, everything works great as far as the apex'i turbo timer and the 5th gear switch. It turns off, and gauges work in all gears. What all exactly is controlled by the meter fuse itself? I just dont want to run the car not knowing what ALL it controls, ya know?

The meter fuse feeds power to a lot of things, including the cluster, warning lights, brake lights, cruise control, heater and the A/C. When the fuse is blown or removed, do any of these systems still work? If they do, I'll bet the previous owner used the B/Y wire from the meter fuse to power the turbo timer. The additional draw of the timer may be too much for the little 7.5A fuse to handle, when there is also draw from other areas. The diagram doesn't show the 5th gear switch or ECU as getting power from the meter fuse, but the switch is related to the shift up light in the cluster, which does get power from it.

http://members.cox.net/linspace/meter%20fuse.JPG

Yea, this is insane. With the fuse pulled, all cluster and warning lights work. As far as the timer, theres no splicing. they made the wire harness that connects directly to the ignition, then to the relay. The only wires left for the timer are a ground, which is good, and the grey wire to the parking brake (for atx), and a white wire that splices into the 02 sensor wire on the ecu (which isnt used). Those wires are optional anyways, all I want is the timer to work. I already have aftermarket gauges for everything else. Havent checked the heater yet, will do that in the morning. But everything else seems fine now. Who knows?

Figure out where the power for the timer comes from. Maybe the B/W wire in the diagram, that comes from the ignition switch & also runs to the meter fuse? Somehow the wiring changes for the timer are allowing power to that B/Y wire, even if the fuse is blown/removed. There has to be something else that was changed, other than just a pre-made harness connecting to the ignition.

And to be honest, a turbo timer is totally unnecessary with a water & oil cooled turbo. If you ditched it altogether, it wouldn't hurt anything. But just get things working one way or the other. I think some time tracing the wiring & noting all the stock wire colors will eventually lead you to the problem.

Yea, i was comtemplating that yesterday.. but decided not to because, well, i cant read electrical diagrams. lol if it were a mech issue, id have no problem ripping things apart and finding it in the fsm. i just dont trust myself with reading diagrams. i can wire accessories and stereos like a mo-fo, but when it comes to specs and stock charts, im useless and im not afraid to admit it. I really appreciate all your help on this one man. guess ill just clean things up and leave it as is.

Well, a guy at work, whos an aircraft electrician, said hes willing to bet that the switrch itself is bad. I have a spare gearbox at home, so i guess ill pull the switch, check for ohms, then compare the ohm check with the switch on the installed transmission. if the numbers are different, ill change it out and see what happens. Id still like to get a handle on why the damn timer stays on with the switch unplugged though. Ill let ya know what happens tomorrow when i get a chance to try this stuff. any new ideas, please feel free to let me know!

k, i been searchin on here and see that people been pullin and cleaning these switches up. i pulled the one from my spare gearbox, and started cleaning it... after bout half a minute, i realized that if i really gripped it with both hands with a rag, and twisted it, the 2 halves would spin in opposite directions. is that bad? or do the halves come apart somehow? what do people clean, just the spring and the contact? or do they take them fully apart?

I know the usual reason for cleaning them is because the reverse switch half of it eventually gets overwhelmed by the current passing through it for the reverse lights. The contacts get toasted and need to be polished. But I've never taken one apart myself, so I can't comment on exactly what you'll find inside.

changed out the 5th/rev switch, and removed the turbo timer. now that shes back to stock, the only way to turn off the vehicle is to shift into 5th gear. same as when the turbo timer was installed. i now know that the timer should have nothing to do with it. what would this be telling me about the 5th/rev switch? seems like the ignition, for some reason, needs power from it to turn off. where can/should i start looking? and another thing, with vehicle running, sitting still, when i shift to 5th, the rpms drop about 200-250, and slightly surges up and down. HELP!

ok, got under it, and started peeling the looms back. found several burnt wires before it meets the rest of the engine harness. before they were found, with everything hooked up, pulling on the loom would start the cooling fan. anyways, replaced all the burnt wires and left the 5th gear switch unplugged because the wires still get hot as hell when shifted into 5th. i tested the wires, and one wire (B/BL) has constant 12v, and the Black wire has none. is that the way its supposed to be?

The wires running to the 5th gear switch are supposed to be power & ground. That's normal. Inspect all of the wires coming out of the ignition switch. There's bound to be some splicing somewhere. Maybe even take the plastic cover off of the steering column to get a better look. Turning the car off should have nothing to do with 5th gear.

well, i said hell with it. being that the 5th/rev switch is good to go, now my room fuse keeps blowing. i started this morning on pulling the entire harness out. gonna bench it this weekend and go through all harnesses one wire at a time and replace as necessary. i got a quick question as far as a wire is concerned.. theres a B/W wire that connects to a shielded wire in the harness around the area that is between the coils. should there be a connector on that to plug into something? it just looks wierd.

I'm not sure what wire you're talking about. It's in the engine bay, and somewhere near the shock tower? Take a picture, and I can probably figure it out.

ok, keep your eyes open. ill take a pic in the mornin and post it up.