no current to power seats, 96 Cobra

[rsa4046]

Recently rebuilt and reinstalled power seats on a 1996 Cobra. Both seats have their current supplied from separate two-wire leads coming up through holes in the floor directly under the seats. These connections supply current to the driver's side 4-way adjustment + lumbar air bladder pump; passenger has air bladder pump only. The manual indicates these leads are fused only at the "high current" fuse box (the one in the engine compartment, not the one under the dash, fuse location = CIG LUM, 30a). This fuse is good, and grounding the hot side (with key at ON position) shows 12.5V. The manual shows this circuit also includes the cigarette lighter, which works fine. However, the seat leads are dead (0V tested with key ON)! Wiring diagram in Haynes manual is incomplete and doesn't show power seat wiring. Anyone know if there is another fuse or fusible link in this circuit? I've tested ALL fuses in both boxes, just to be sure. The seats work fine if hotwired to the battery, so the problem is definitely in the circuit, not the seats themselves. Thanks much in advance --

 

[5.0's 4 ever]

The power seats actually run off their own 25A fuse in the engine compartment fuse box, not off of the cigar/lum fuse. You said all the fuses were fine. I would check to make sure you have power at that fuse, if you do I would check the next connector inline with the circuit for power on LB/W. Its connector 105, its black with 24 terminals. It located back near the drivers side rear of the engine compartment.

 

[rsa4046]

The power seats actually run off their own 25A fuse in the engine compartment fuse box, not off of the cigar/lum fuse. You said all the fuses were fine. I would check to make sure you have power at that fuse, if you do I would check the next connector inline with the circuit for power on LB/W. Its connector 105, its black with 24 terminals. It located back near the drivers side rear of the engine compartment.

Thanks 5.0's 4 ever, am checking it now ...

 

[rsa4046]

OK, within the engine compartment fuse box, location labeled 'STD 3' on box cover must be the one for the power seats (25a fuse, 3rd closest to engine centerline in column of fuses closest to front bumper). This position is marked 'Int. Lamps' in diagram of owner's manual (p. 304), but all interior/instrument/glovebox lamps work with this fuse pulled. Fuse was okay (replaced anyway, no change).

With the fuse pulled and volt/ammeter test leads bridging the fusebox contacts, I get

KEY ON: +4.76V
KEY OFF: +12.40V

Voltage between fusebox contacts and battery ground terminal:

KEY ON:
+12.23 V (hot? side contact, closest to firewall)
+7.43 V (earth? side contact, closest to front bumper)

KEY OFF
+12.45 V (hot? side contact, closest to firewall)
0.0 V (earth? side contact, closest to front bumper)

I couldn't locate any 24 terminal connector on driver's side rear of engine compartment, but I will keep looking. Do these voltages suggest the circuit's OK?

 

[5.0's 4 ever]

The fuse you pulled was for the brake on/off switch and brake pressure switch. You want the fuse in that same row but is closest to the engine. To the left of the fuse you pulled out should be a 20amp for the fog lamps and horn and to the left of that should be the 25amp for the power seats. Its hot at all times so you should have 12v on the right terminal(closest to the firewall). The 20 terminal connector looks like its ran through the fender. You can see the back of it if you look under your dash to the left.

 

[rsa4046]

5.0's 4 ever:
Sorry for the long delay, had a family emergency to deal with. Thanks very much for your help: can you look at this page from the manual and tell me if it's correct?

http://forums.stangnet.com/attachment.php?attachmentid=29359&stc=1

Thanks again --

 

[Saleen201]

on a side note, have you ever had weld in sub frame connectors installed?

 

[5.0's 4 ever]

The top fuse spot that you are pointing to in that picture is for the 25amp power seats. I don't know why it says "L. Spd. EDF Mtr. 10amp". I have my own ford 96 mustang EVTM infront of me and there is no such thing.

 

[rsa4046]

on a side note, have you ever had weld in sub frame connectors installed?

Saleen201: No subframe connectors.

The top fuse spot that you are pointing to in that picture is for the 25amp power seats. I don't know why it says "L. Spd. EDF Mtr. 10amp". I have my own ford 96 mustang EVTM infront of me and there is no such thing.

5.0's 4 ever: Replaced 10a (the only one I failed to test , just visual inspection) with 25a fuse, power seat's working again . Thanks so much for your help!

 

[rsa4046]

addendum

As an aside, I also noticed that the online manual published by FMC (see the thread http://forums.stangnet.com/showthread.php?t=510343, thanks Venom Nitrous!) has the proper fuse locations, labels, and amperages, so Ford has corrected the misprint(s) in the "original" paper manual.

 

[5.0's 4 ever]

Glad to hear it