2003 Mustang adjustable illumination fuse keeps blowing


New Member
Aug 28, 2020
I've got an 03 ford mustang (6 cylinder) that I purchased about 5 months ago, about 2 months into owning the vehicle I went to turn on my lights and noticed the instrument cluster lights were not working. Checked adjustable illumination fuse (37 10a) and it had blown, replaced it only to have it blown instantly again upon turning lights on. Any advice would be appreciated.
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SN Certified Technician
Aug 14, 2009
Houston Texas
If this were my car I would pull the head light switch and inspect for evidence of over heating. If any is found replace the head light switch. These fail at a fairly high rate.

If none is found I would use a regular test light to see if there's a short to ground on the circuit. Pull the fuse. Put the test light pig tail on a known good battery positive. Confirm that the test light does light when touched to a known good ground. Does the test light light brightly with the fuse removed when touched to the "load" side of the fuse? If so, there's a short to ground in the circuit.