Fuse blows when I shift into reverse

[dodecahedron]

Hi all,
Having some fun electrical issues with my '88 240 wagon 5spd. I replaced all of my fuses, and now when I shift into reverse, the fuse in position #12 from the top (or position #5 from the bottom) blows whenever I shift into reverse. Additionally, all of my taillights have stopped working (running lights, brake lights, etc).

Before I dig into this one, is there anything I should check first? And does anyone have any good diagrams of the taillight wiring for 240 wagons?

Thanks!

 

[TilledChip]

Dumb question but did you replace the fuse with the right one?

 

[cleanflametrap]

The special wire used to connect parts of the car that move with respect to each other has lost its insulation and most likely is shorting to the transmission housing. This is the high strand count, silicone insulated wire made to be flexible, and in your case, used to wire the reverse lighting switch on top of your M47.

Tail lamps and brake lamps may have separate reasons for failure, but one component is common to both, plus the headlamps; the bulb failure warning sensor above your left knee. Take a look in the sticky thread "volvowiringdiagrams.com down for good" near the top.

 

[ZVOLV]

shorted wiring in the trans tunnel.

 

[dodecahedron]

Dumb question but did you replace the fuse with the right one?

yep, double triple checked the diagram on the fuse cover

The special wire used to connect parts of the car that move with respect to each other has lost its insulation and most likely is shorting to the transmission housing. This is the high strand count, silicone insulated wire made to be flexible, and in your case, used to wire the reverse lighting switch on top of your M47.

Tail lamps and brake lamps may have separate reasons for failure, but one component is common to both, plus the headlamps; the bulb failure warning sensor above your left knee. Take a look in the sticky thread "volvowiringdiagrams.com down for good" near the top.

Thanks, I'll check this out! I have noticed the bulb failure light flickering on and off throughout all of this....

 

[dodecahedron]

The update on this thread is that all sorts of electrical problems are popping up now, and I may be in over my head. The alternator no longer charges, the dashboard flickers all the warning lights intermittently, turn signals stopped working, and the bulb failure light flickers at me angrily most of the time.

The electrical demons are winning this one right now, that's for sure

 

[Radtap]

Does the car have evidence of rodents? Sounds like the wiring harness is shorting out or falling apart

 

[2turbotoys]

Did you fix the wires on the transmission yet?

 

[conehead]

88 would be right on the border of when they switched from the soy based wire coating right? Checked all the grounds?

 

[2turbotoys]

88 definitely had the biodegradable wiring. I had one, cleaned the engine bay and all of a sudden a ton of bare wires all touching each other.

 

[Radtap]

88 would be right on the border of when they switched from the soy based wire coating right? Checked all the grounds?

1988 is also 35 years old now, just because it was updated materials doesn't mean it's still good after 35 years of road grime, engine oil, heat and cold, possible water leaks, vibration, stress.

 

[conehead]

Yep, I'd probably be looking on Dave Barton's website about now

 

[white855T]

88 definitely had the biodegradable wiring. I had one, cleaned the engine bay and all of a sudden a ton of bare wires all touching each other.

88 already had improved wiring. It was by 1987.5 that wiring changed. Not saying wires weren't bad because I've seen some 88 models with bad wiring.

 

[white855T]

The update on this thread is that all sorts of electrical problems are popping up now, and I may be in over my head. The alternator no longer charges, the dashboard flickers all the warning lights intermittently, turn signals stopped working, and the bulb failure light flickers at me angrily most of the time.

The electrical demons are winning this one right now, that's for sure

Replace wires for the reverse lights. Dave Barton has harness just for this(not cheap). Replace alternator, replace bulb failure relay. It might seem a lot but it's an old car with really common problems.