Has anyone swapped the idiot light gauge cluster to the ralley dash gauge cluster? I hear there is some wire swaps or something you have to do to get it to work right. Any help would be appreciated. I have a 1972 GS455. Thanks, John
I've done it, but I found an original pigtail to use - you can read how to to the wire swap on George's website at this link: http://www.buickperformance.com/rallygage.htm
Hi John, Since you are doing the swap you may want to add in other options if you don't have them - I originally had the idiot warning lights, regular speedometer, and clock delete dummy gauge - I swapped them all for a ralley gauge, speedometer with speed alert, and a 24hr clock.
I have the clock but don't have a speed alert speedometer. Do you need different sending units also or do the ones for the idiot lights work. Thaks, John
Hi John, You will need new water and oil sending units for ralley gauges. I had to replace mine when I did the ralley gauge swap.
There is also a jumper attachement available from some of the wiring companies that allows attachment to gauge. It probably is a waste however as it is easy to change wires in connector if you are careful. You also need to purchase tach wire for engine compartment and maybe tach wire for under dash. Some harnesses have tach wire incorporated into harness already. Wire for hood tach is probably there as well taped to harness near fuse box. Tough working under that dash especially if you have AC.
I did this conversion on my convertible years ago. I used the correct pigtail and a factory gauge package. Changed the sending units .Everything worked but there is a difference somewhere in the wiring harness for idiot lights. When I go to start the car It will peg the temp gauge when starting. After its running its fine. I think it has something to do with the feed to the idiot lights when starting. I tore this thing apart a couple times looking for anything different but no success. My second conversion yeilded the same results so I ended putting the idiot lights back in. I would love to figure the problem out , all I can tell you is its not a ground problem. Any input would be appreciate.
I think I do have a manaul. Like I said it all worked fine but when you start the car the temp gauge will peg when cranking. You don't have this problem with yours? I have done this on 2 cars and both did the same thing. I wonder what gives? I know all the grounds are correct and it's wired correct as I have the factory pigtail. My car has seat belt warning.
I think it's a normal reaction to voltage drop when the starter is engaged. Just checked my car, does the same. Check section 120-23.d in your manual. Describes how the sender for lights will peg on cranking, turning on the light. Pretty sure the sender circuit for the gauge will react the same, putting the needle at max. temporarily.
Ok i ill get in there and look. That would be funny being i have been racking my brain trying to fix this thing. Thanks for the info heading to the book :TU: now
Not as funny as I looked the day I buttoned up my first engine rebuild, which was this car. Chest stuck out a mile, all grins from ear to ear. Ready to drop it in.......careful, don't scratch the red paint! That's when I found this extra piece on my socket tray.....oil slinger!
FYI I had to find a oil pressure sender on Ebay - $35 - NEW Napa had the temp sensor for a gauge - $7
just as I suspected the wiring harness between idiot lights and the gauges do have one difference. you must clip or store the Dark green wire at the ignition switch in Grd1. this wire is supplied 12v at cranking and is jumpered/ connected when key is turned to start position and then disengaged after returning to run. Gauge cluster harness doesn't have this and is a direct run from sender to gauge. You will ruin your gauge over time if not disconnected. If removed gauge will function fine and not peg when starting. look at the chassis electrical for both in manual.
Sharp eyes! I had not ever compared the two drawings before. You are absolutely right. Are you able to get at the splice point easily? Hopefully not up inside the column.
thanks...I haven't had the time to do it yet. It should be as simple as just unpluging the wire on that terminal from the ignition switch on top the column. Look for a dark green wire. If it spliced somewhere else will not matter being you removed its source . I will get time to try it this week.
Look at the similar drawing for a car with indicator lights. Trace the dark green from the temp. light & you will see it has a "T" splice under the dash. One leg goes to the sending unit, one goes to the ignition switch. From what I see in the '71 manual, go to the detail under steering column assemblies. Fig 90-79 in the '71 book, steering column electrical connections. One of the two connectors at the ignition switch has the dark green. This is where I suspect would be a good place to cut & cap the dark green. Planning this Winter to modify my own, no experience yet.
