Spedometer and abs are out after clock timing fuse blew and was replaced.. all the abs fuses in fuse box one are good. is there a hidden fuse somewhere or something I missed in a 1994 VDP? checked left rear speed sensor and its good, so whats stopping the speedo signal? can a blown ABS module do that?

 

Just a suggestion (it may not be the cause) but 94's are known to have problems in the fuse boxes, i.e. dry joints and cracked connections.

Reflowing the solder usually fixes them up.

Fuses can test "good" but often the problem lies in the circuit board joints at the back of the fuse box - the front circuit board supports the fuses and the connections pass from there to the back board and from there to the harness.

Both footwell fuse boxes had bad joints on my 94.


Larry

 

Hi Steve,

On the '93/'94 cars the speedo signal comes from the right front wheel speed sensor by way of the ABS module, which passes along a digital signal to the Instrument Pack, which forwards it to the Engine Control Module (and either directly to the Transmission Control Module via serial communications or by way of the ECM - I can't remember off the top of my head). A problem with the front right wheel speed sensor or the ABS module can definitely result in the loss of speedo operation as well as other issues.

I haven't had to deal with any ABS module problems, but some owners have. I seem to recall that cold solder joints have been known and also water ingress due to leaks around the fuel filler neck gaiter. For more information search this forum as well as the archives at the Jag-Lovers forum.

Regarding Larry's good suggestion about fusebox solder joints, the photos at the link below may be helpful:

Welcome to Jag-lovers - Members Photo Viewing Page


And here's a link to the '94/'94 XJ Electrical Guide, which includes the schematic for the ABS system (and all the others):

http://www.jagrepair.com/images/Auto...ec%20Guide.pdf


Cheers,

Don

 

Solved the problem. The ABS computer in trunk was slowly dying and the fuse blowing finished it off. grabbed a spare from the junk yard and everything came back and ABS works properly too! The symptom that worried me before it went out completely was that brakes would be hard at high speeds and shorten my stopping distance by a big margin but operate normally at city driving.