Fuse box, an internal PCB or similar?
09-16-2022, 12:02 PM
#1
Rennlist Member
Thread Starter
Fuse box, an internal PCB or similar?
Hi guys.
I have a fuse box that has developed two faults, the internal connections from a fuse to a relay is cut.
The connection between Fuse 13 (cabrio roof) and relay R21 (cabrio roof) is simply not there. The same between Fuse 15 and R51 brake booster pump. This results in a non-op (C4) brake booster pump as well as cabrio roof. They operate normally if I bridge these points, so I am sure the internal connection is broken.
I have never dug deep into this before, but the schematics tell me that these internal connections are inside the fuse box enclosure, and not wire bridges on the connectors underneath it.
Has anyone opened the fuse box and can tell if there's a kind of printed circuit board or other internal circuitry that should carry these internal wiring connections?
By "opened", I mean to disassemble the plastic enclosure to reveal the copper relay and fuse holder clamps, not only taking out the complete fuse box out of the surrounding metal tray in the frunk.
X-posted on the 993 forum as well, since this is the same type of fuse box.
Thanks in advance,
Tore
I have a fuse box that has developed two faults, the internal connections from a fuse to a relay is cut.
The connection between Fuse 13 (cabrio roof) and relay R21 (cabrio roof) is simply not there. The same between Fuse 15 and R51 brake booster pump. This results in a non-op (C4) brake booster pump as well as cabrio roof. They operate normally if I bridge these points, so I am sure the internal connection is broken.
I have never dug deep into this before, but the schematics tell me that these internal connections are inside the fuse box enclosure, and not wire bridges on the connectors underneath it.
Has anyone opened the fuse box and can tell if there's a kind of printed circuit board or other internal circuitry that should carry these internal wiring connections?
By "opened", I mean to disassemble the plastic enclosure to reveal the copper relay and fuse holder clamps, not only taking out the complete fuse box out of the surrounding metal tray in the frunk.
X-posted on the 993 forum as well, since this is the same type of fuse box.
Thanks in advance,
Tore
09-16-2022, 03:55 PM
#2
Rennlist Member
So I have a little bit, but not super deep. What I recall is the central electric box is basically a retaining system for a whole bunch of plugs that are crimped to pins to the harness on the back side. I don't recall a PCB there, but I didn't look all the close. Unlike the old 914 engine bay fuse board, which was a big PCCB encased in epoxy that always breaks.
You can see a poor picture here:
https://rennlist.com/forums/964-foru...l#post17127327
You should be able to trace to the fuse box wire on the back side and see the crimp points. I assume you have the full wire diagrams?
You can see a poor picture here:
https://rennlist.com/forums/964-foru...l#post17127327
You should be able to trace to the fuse box wire on the back side and see the crimp points. I assume you have the full wire diagrams?
09-17-2022, 05:14 AM
#4
Rennlist Member
Thread Starter
Thanks.
I took out and dismantled the fuse box, this wasn't as bad as I thought it would be. A 30-minute job, out and in again.
This proved to be another case of loose 964 fuse/relay holders. My probes did not even touch the copper clamps when poked them down through the opening. Case closed.
Tore
I took out and dismantled the fuse box, this wasn't as bad as I thought it would be. A 30-minute job, out and in again.
This proved to be another case of loose 964 fuse/relay holders. My probes did not even touch the copper clamps when poked them down through the opening. Case closed.
Tore