At lest is less complicated then Cavalier and other electronic dashes so less things to fix.
For this job and related use thin flux core lead/tin solder and 25w (or less) iron. You want to heat fast but not "melt" the glue holding copper to board or cook other parts.
Thin like under 24awg size wire like I have 0.
032in. You use more but melts faster then most solder sold at normal retail stores.
Even then May work for now.... but keep a easy way to undo the mod if used in Fiero etc.Because?
Many car electric parts die from old capacitors and other small items in/on a device on top of crap solder joints.
Electrolytic caps isn't only cap type that have problems from old age even ignoring China "poison" cap problems ate thru the can etc.
Like you can fix "Gen 2" Blue Dingy Thingy by re-flowing a joint or three like shown in cave page Chime Unit
but all versions can die from bad caps etc too.
Is part of why many stop selling "radios" using the same Fiero plug.
To make them reliable to give even a small warranty need a lot of work to "Re cap" them etc and see little point or profit doing that.
A big reason is a Car Cabin can easily reach 160 to 200+ °F parked outside even on cool days to bake them.
Example see http://www.fiero.nl/forum/Forum2/HTML/141784.html
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave