Another Rally Gauge problem

SLICK78

Dragway Regular
Aug 1, 2009
1,120
0
0
La Porte, Tx
OK guys need some help on my rally gauges only my fuel and speedo work, and it has been that way since I got the car well when I put it back together from swapping to leds my temp gauge is reading. Is there a way to check the oil press and volt gauges to see if they work before I spring for new senders. Or it there some common problems with the rally gauges that I need to look into first? I would really like to keep the stock gauges so making them work is a must for me, I have to have gauges and have added them to all my cars that didn't come with them, so it was a nice change to get one with them factory then I noticed they don't work ](*,)
 

ScotSea

Frequent Racer
Sep 21, 2003
381
0
0
Since the temp guage started working once you pulled out the pod and put it back, it suggests a connection problem.

I would pull it out one more time and clean the connections on the back of the printed circuit board. Be very gentle, as it is probably quite fragile. Also clean the connector in the dash. Be gentile. There are multiple connections to be cleaned. Be gentile. The clamps that grip the guage screws also make a connection to the printed circuit board. These may need to be cleaned too. Did I mention be very gentile?
 

SLICK78

Dragway Regular
Thread starter
Aug 1, 2009
1,120
0
0
La Porte, Tx
I havent pulled the whole thing out just the gauges out to replace the bulbs how do you take out the whole thing I'm guessing the 10mm nuts behind the gauges and what is the best way to clean the connections
 

Doober

Moderator
Jun 2, 2003
14,704
1
38
Catalina, AZ
www.cardomain.com
I used some very fine sandpaper, and thought I was being gentle, but it still managed to wear more on the traces than I'd hoped. Another option is to go the route I did (from the pics you saw on GBF). It's not difficult, I double- and triple-checked the traces to make sure I had the right connections to start with. Then I tied the +12v and ground connections of the gauges together, and created the leads for each of the 3 gauges with sending units (oil/temp/fuel). They all went to the white molex connector I pointed out (got it from Radio Shack for a buck or 3, came with all the pins which I soldered), and I tied the opposite side of that connector in with the factory wiring. Like I said, I don't trust the age of these circuit sheets (current - SECOND - one is starting to separate at the edges btw), and I'm not quite ready to pay the $$$$ for a reproduction piece (planning on aftermarket gauges anyway). That took care of my gauges reading wrong when I turned the lights on, but still doesn't take care of the semi-dim illumination (which you solved with LED lighting). Since I picked up a Grand Prix dash I don't plan on using this setup when I put the '78 back together anyway.
 

ScotSea

Frequent Racer
Sep 21, 2003
381
0
0
Just those 10 mm nuts, and it should be in your hand. The small cable for the PRNDL will be attached to the steering column still. But in the previous pictures, you had that out already.

A pencil eraser may do the trick, but be very gentile. Move the eraser along the trace toward the end of the trace, never away from the end of the trace.

You may also find a bad connection for that upper left dash light.... You can take the lamp holders out and clean the traces underneath those too. Look for a bad connection (a hot spot) for one of the lower dash lights. I have seen a number of those.
 

SLICK78

Dragway Regular
Thread starter
Aug 1, 2009
1,120
0
0
La Porte, Tx
thanks guys I will give it a shot this weekend... Doober do you have a wireing diagram for your wiring you did since they are all the same colored wires lol
 

Doober

Moderator
Jun 2, 2003
14,704
1
38
Catalina, AZ
www.cardomain.com
No, that's one thing I didn't do. You can follow two of the traces on the board and find which ones are common, those are + and ground, you just need to find out which ones are which. Whatever stud is leftover on the gauge is for the sending unit. I just used the diagram from the tech portion of the site for the wire coloring. I believe green is temperature, tan is oil pressure and pink or purple is fuel level.
 

SLICK78

Dragway Regular
Thread starter
Aug 1, 2009
1,120
0
0
La Porte, Tx
thanks I will give it a shot this weekend
 
On all the gauge cars I had, I had to remove the whole gauge housing/pods and clean the contacts where the dash and the pods meet. Then tweek the copper tangs so they were tight against the ribbon connector
 

SLICK78

Dragway Regular
Thread starter
Aug 1, 2009
1,120
0
0
La Porte, Tx
tried that still no volt or oil press guage
 

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