If your car didn't come with head-up display (HUD) or a Trip Computer AKAriver Information Center (DIC) and you want to put them in you can. If your car is in a model year before 2000 you probably have some or all of the plugs already in your dash, but if you have a 2000 or later GP you'll probably have to splice some wires.
Splicing wires isn't hard to do, the DIC installation is easier since most of the wires are cut right off of the old DIC connector so it's just a butt-end connection that has to be made so if your nervous or are a beginner, start with this to get the hang of it before you tackle the HUD. Tapping into wires takes a little more skill but is still very easy. I use BackInBlack's twist 'n tape method and have had no problems whatsoever. He has a great page you can see here:
DIC installation may be as simple as plug-and-play if you already have the harness, but if you don't, not to worry. Follow the wiring table below to splice in wires and you'll be up and running in no time. The DLC wire is the hardest one due to it's tight location, all the others are easy. The DIC is held in by clips on either side only, squeeze these and pull it out, there's some rattle insulator padding back there that it might be stuck to so you might have to wiggle it out.
NOTE: If you have a 97, ONLY use a 97 DIC. It has the "Check Tire Pressure" light on it. No other year has this light. The 89-03 DIC's are all interchangeable. But you can't use a 97 DIC on a 98-03 either. I can't stress this enough, don't waste your money on a DIC that won't work. 97 DIC's ONLY work on 97's, 98-03 DIC's ONLY work on 98-03's and are interchangeable. Another note is that the GT DIC's and GTP DIC's are different. GT DIC's for 98-03 say "TRAC" on the right button, GTP DIC's for 98-03 say "TCS" on the right button. Try to get the correct one for your car (GT=TRAC, GTP=TCS) or you'll have issues with the "TCS off" indicator light being inverted. You can fix this by doing some extra work but who wants to do MORE work? Moral of the story...just buy the right one!
DIC Wiring Diagram
HUD installation is much more involved since you need to splice more wires, almost all of them will have to be tapped instead of butt-connected, and you have to cut the dash. If this scares you, good, that way you'll be more careful! All 97-03 HUD's are the same for both GT's and GTP's so there's no issue of fittment here. The only thing you'll have to watch out for other than if you have the plugs back there or not is the wire B4 on the instrument panel connector 1 which will be missing if you didn't have the plugs. This connector will light up the little gas pump symbol on the HUD when the low fuel light comes on in the dash. If you don't care about this, don't worry but if you want it to work, you'll have to steal one of the connectors out of the base DIC connector (same style) to clip into there so you can splice it. All other wiring is straight forward.
HUD Wiring Diagram
Cutting the dash will be easiest if you have a dremel tool. Watch your window when your cutting, I nicked mine and there's an inch long etch mark right in my field of view . You'll have to get the appropriately coloured dash piece from someone, remove the front piece by carefully prying up all along and pulling up and out. You'll lose some clips...hopefully your HUD piece has them all still. Lay the HUD dash piece over where it clips into the dash and draw a close outline around the piece in fromt of the driver with white chalk. Take the dash peice out and draw another line about an inch inside of this line. You can now do anything you want to the dash inside the second line because you know it'll be covered by the dash piece. Cut out the dash roughly in the shape of the pics below, keep a rag or shopvac nearby, it's messy business. You'll have to punch holes and cut some of the dash pad out from around the three areas where the clips closest to you pop into. Be careful here as well as cutting out space for the harness since these are the two areas that come closest to the edge of the dash piece. You don't have to cut the trim right along the bottom of the windshield but there will be a clip that the part you're cutting out is attached to that will be a pita to get out. Clip the HUD in (don't worry about putting the front screws in, they're not needed), clip the switch in, turn your car on, and test it all out (speedo, dim, up/down, turn signals, radio, CD, high beams) to make sure everything's good before you clip the dash piece on.
Here's a little pic of some images I pulled out of a search:
1, 2: Factory plug locations (approximate)
3: 3 clip holes for the HUD dome clips
4: outer line
5: inner line
6: factory hole (pic is stretched vertically)
7: HUD in cut hole
There you go...you've completed the HUD and DIC installation primer. Now do a little more searching if you have any other questions. You can also email or PM me as per the details on the bottoms of the wiring tables. The tables in this post will always be the most current of any one you'll find since I'll be reposting them here any time there is a change. Just a couple more tips; don't rush, and MAKE SURE you don't have the stock plugs in there before you start splicing.
Thanks, and good luck B)