fuse blows after jump start

[mproe]

Since we jump stated our 99 Escort coupe, the TAIL fuse, controlling the tail lights and instrument panel illumination, blows out when the car starts, accompanied by warning beeps. Any advice? Thanks.

[mightymoose_22]

Check and see if any of the light bulbs have blown.

I believe this is this sort of reason why the ground for the dead vehicle gets connected to the block and not to the neg terminal. Not saying ya didn't do it that way... but something to think about if you connected all four ends to the batteries.

[mproe]

Nope, grounded to the frame, but didn't turn on fan and other accessories when jumping, as instructed in the owners manual. All 4 bulbs in the tail light assembly seem to be working as signal lights. Maybe different elements are used for tail lights? Didn't try to locate the instrument panel bulbs; would a bulb being blown out cause the fuse to blow?

[mightymoose_22]

I have had a bad bulb cause weird things before... not sure if would cause a fuse to blow. Was worth checking though.

[Selectron]

I have a different model (UK '95 Escort 1.8 diesel, manual transmission, estate car version) so I can't help with specifics, but I'd start by isolating as much of the circuit as possible. Presumably the wiring harness connects to each rear light cluster via a connector - I'd unplug each of those, and also unplug the connector to the licence plate lamps (if they have their own connector) and then I'd try again and see if the fuse still blows. If it doesn't blow then that suggests that one of those rear clusters, or the licence plate illumination panel, has a short-circuit. I did a quick search here on the forum for tail fuse and apparently, corrosion in the rear light clusters can be a problem on Escorts, so corrosion may be causing a short-circuit. If you have access to a multimeter, you can find that by resistance readings, or if not then it should still be possible to find it by visual inspection. If the fuse still blows with those rear items disconnected then I'd try to disconnect the dashboard illumination lamps next, and see if the fuse still blows. I'd leave that till last though, because being inboard the vehicle, corrosion is less likely, plus it's likely to be an awkward task. If you have access to a wiring diagram, have a look and see if the radio is fed from that same fuse and if so then eliminate it by disconnecting it (assuming you have the security code to hand so you can re-enter it later). As for the beeps, I don't know what that might be, because the only time my Escort ever beeps is when I leave the lights on and open the door, at which time it will beep to remind me to switch them off. Just out of curiosity, what was the reason for jump-starting the car in the first place? Also, did the fuse problem precisely coincide with the jump start, and had the car been in regular, recent use prior to that?

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Here are some links to threads referring to tail fuse problems:

http://www.automotiveforums.com/vbul...d.php?t=552299
http://www.automotiveforums.com/vbul...d.php?t=410636
http://www.automotiveforums.com/vbul...d.php?t=482339
http://www.automotiveforums.com/vbul...d.php?t=209108

You can find more by using the advanced search option, but those appeared to be the most relevant.

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[Selectron]

Also, is the licence plate mounted to the main bodywork, or is it attached to the lower portion of the trunk lid? If it's the latter then there will be a flexible wiring loom carrying the licence plate electrical wiring from the chassis to the trunk lid, and this may have frayed and shorted so give that a thorough visual inspection.