Gauges React to Internal Light Switch

[euphorium]

I have had problems with the gauges responding to the illuminator adjustment switch.

a) The tach bottoms out when the illumination bulbs turn on.
b) The fuel gauges goes up about an 1/8 of a tank giving a misreading.
c) The OP gauge goes up about half a mark.
d) The Voltage gauge goes down to about halfway between the middle of the gauge and the -30 mark. Even though the battery is fully charged.

I have rewired the dash 3 times, replaced all ofthe connectors with new ones and continuity tested each wire. Sanded all of the contacts (which fixed the turn signal lamps from lighting up on both sides to show actual direction selection and the bulb intensity of each gauge illuminator and component)

I am sorry if I don't use the correct terminology. I am an IT Specialist and not a mechanic. However, the schmatics and diagrams aren't rocket science.

Any help would be greatly appreciated. This has been driving me *hehe* for 3 weeks now.

[skibby]

Im kinda having the same problem with my GT I think I have narrowed it down to the flasher wiring. You might try looking in the sterring column itself? Iam about to tear into mine based on what I am finding on pg 111 of the 1976 opel chiltons manual. I can e-mail you the diagraghms It might take a day or two as I need to track down a scanner but the manual I have has a very clearly written Diagram that even I can make sense of and that saying somthing. Anyway let me know what you find and I'll do the same. Thanks!

Skibby

[euphorium]

i was thinking that yesterday, but forgot about it until you mentioned it. I was rewiring the engine compartment yesterday and when i reconnected the battery cable. I headr a click. so I started tapping the ground cable off and on the battery post. Everytime I would hit the post. The Flasher switch behind the dash would engage and disengage when the cable was disconnected.

I pulled the switch and tested again and the clicking stopped. Which led me to believe that my switch is bad? however, without the switch my signals dont work. So i had to put it back in.

On top of that, my battery keeps ending up being dead after 2 days sitting

Which is what started me on this rewiring project 3 weeks ago. LoL

Now I have just run into more problems....

[First opel 1981]

Originally Posted by euphorium i was thinking that yesterday, but forgot about it until you mentioned it. I was rewiring the engine compartment yesterday and when i reconnected the battery cable. I headr a click. so I started tapping the ground cable off and on the battery post. Everytime I would hit the post. The Flasher switch behind the dash would engage and disengage when the cable was disconnected. I pulled the switch and tested again and the clicking stopped. Which led me to believe that my stich is bad? however, without the switch my signals dont work. So i had to put it back in. On top of that, my battery keeps ending up being dead after 2 days sitting Which is what started me on this rewiring project 3 weeks ago. LoL Now I have just run into more problems....

That doesn't necessarily indicate a bad turn signal flasher. Your turn signals aren't hot when the ignition is off so the flasher shouldn't be clicking. What IS live when the ignition s off is the emergency flasher. Since it is rarely used, it can go bad pretty easy without giving any other signs of problems. Also, if memory serves me, the emergency flasher is wired through the brake light system which would be a potential link in the short when pressing the brake pedal.

This would explain why the battery goes dead in 2 days also.

HTH

[tekenaar]

. . . make absolute sure you have a good instrument GROUND!!! . . . this is a known problem in Kadetts because they're grounded to the windshield wiper motor. I added an additional ground wire and solved this problem on mine . . .

[euphorium]

Oh mercy.. this is getting deep. Because the RedLight next to the signal indicators was at a constant red before I cleaned and redidthe wiring on the dash. Nowit goes in and out when I pressand depressthe brake pedal.

The note about the emergency signal switch being constantly active makes sense. I just tested the emergency signals tonight and they are working like they are supposed to, so I am to assume that the problem with the battery going dead is something else.

I guess I'll move on to the headlights since they need to be rewired for safety reason anyway. I am just hoping I can get this dead battery issue solved soon. I just bought an Orion Gel Cell 3 days ago and dont want to burn it up from bad wiring.

Note:
a) I recently had the alternator rebuilt (upped to 40 AMPS)
b) Replaced the Voltage Regulator
c) Replaced Ignition Coil
d) New Wires
e) Plugs etc.. etc..

Basically a new starter system. So I know that is not the issue. (I mention this because the alternator / generator was damaged andgrounding internally.)

[timemachine]

This is a pretty common problem for vintage cars of all types. Since you're talking about "illuminator adjustment" I assume you're talking about an internal dimmer for gauge lights. These controls often gain internal resistance through corrosion which can cause intermittent contacts and simply rotating them vigorously can often cure the problem. The easiest way to stop this problem is to wire the input and output leads together to bypass the dimmer, which, while it defeats the dimmer, the lighting in these cars has never been excessive to me.

However, if the dimmer movement causes gauges to malfunction, there may be an internal short which calls for the same solution, but I'd first make sure that all the fuse box contacts with fuses are clean and uncorroded.

Finally, keep in mind that the Opel's 35A alternator in combination with varying degrees of old corroded contacts causes voltage drops all over the place that might first appear in higher resistance corroded contacts on the gauges (which are very sensitive to voltage changes by design). For example, merely turning on the headlights will often cause the oil pressure indication to drop. It's not something that affects your car's performance or safety, but it is another reason to make sure all the contacts you can reach are clean and tight.

I prefer contact cleaner or a solvent and a rag over sanding connectors, since the latter can remove plating and lead to corrosion. Once you've cleaned old copper or brass, rubbing a pencil over the surface before remounting is a good idea because it adds graphite, which is a good lubricant that helps limit corrosion and preserve conductivity.

Jim

[euphorium]

Originally Posted by tekenaar . . . make absolute sure you have a good instrument GROUND!!! . . . this is a known problem in Kadetts because they're grounded to the windshield wiper motor. I added an additional ground wire and solved this problem on mine . . .

I read that in another thread. Should I run a ground wire from the speedometer connecting points to the ground point at the fuse box for extra measure?

I wouldn't know where else to run it from, since it is a dashboard issue at this time.
Also, my GT Wiper motor is under the grill in front of the windshield. I would post pics but I don't have a pic hosting account yet. Never seemed to have a need for it until now.

[euphorium]

Wow... I didn't expect such a positive support group so quickly... thank you all for your help. I really appreciate it.

In response to Jim.... I would have to agree with the fuse box contacts being an issue, since this is the place of which I am most afraid. The last two times i rewired the fuse box. It took me all of 8 hours each time and lots of continuity testing to make sure I have the right wire to the right component.

I am speaking of the illuminator adjusment switch. It is what affects my gauges the most and the mention of the headlights is a good point because when I flip my headlights. The tach bottoms out like its not working at all, no matter what position the dimmer switch is in.

I will bypass the switch tomorrow and start in on the fuse box.

I will post an update on the results when I complete this next phase.

Thanks again, props to everyone and their efforts.

[hrcollinsjr]

I know I'm repeating some of what others have already said but... I've corrected most dash wiring problems by, first making sure all connections in the fuse panel are good. Fuse contacts are obvious, make sure the wire terminals are clean and last but not always least the 4 brass studs in the center of the fuses are double nutted. You may want to take them loose and make sure ALL of those connections are clean. Second ,as as been mentioned previously, GOOD GROUNDS are important. Third, battery voltage needs to be good. Way too obvious but I'll mention it anyway, make sure all fuses are good. I had a fuse fail and noticed that several of the gauges would read low.

HTH,
Harold

[euphorium]

It took me some time to find the time to attempt fixing the elctrical issues I have been seeing.

So far I have been able to fix the short. I replaced the turn signal ring since my signalarm broke off a few weeks ago, then low and behold. BARE WIRES! I shrink wrapped the hot wire running to the signal ring because it was one of the wires open and I recapped the gray wire that if i remember correctly, manages the internal lighting when the doors are open. Which fixed that problem (I didnt mention it before, didnt care to fix it until I found the short causing the battery to go dead).

As far as the gauges being effected by the illumination switch on the dashboard. I haven't got to that yet. The replacement of all of the wire connectors on the fuse box improved the problem, yet it still happens. I know it is linked to the illuminator switch because I disconnected the hot wire running from the fuse box to the illuminator switch and the tachometer was no longer affected.

Before I bypass the switch. I have a couple sitting in the garage from 2 other Opels I used for parts to make this one. So I will hopefully fix the problem with a switch replacement and if not, I will try a bypass after that.

I will post with an update later.

Thanks again for the help.

[euphorium]

Originally Posted by euphorium I have had problems with the gauges responding to the illuminator adjustment switch. a) The tach bottoms out when the illumination bulbs turn on. b) The fuel gauges goes up about an 1/8 of a tank giving a misreading. c) The OP gauge goes up about half a mark. d) The Voltage gauge goes down to about halfway between the middle of the gauge and the -30 mark. Even though the battery is fully charged. I have rewired the dash 3 times, replaced all ofthe connectors with new ones and continuity tested each wire. Sanded all of the contacts (which fixed the turn signal lamps from lighting up on both sides to show actual direction selection and the bulb intensity of each gauge illuminator and component) I am sorry if I don't use the correct terminology. I am an IT Specialist and not a mechanic. However, the schmatics and diagrams aren't rocket science. Any help would be greatly appreciated. This has been driving me *hehe* for 3 weeks now.

Well, I finally have an update to this thread.

a) I am still having the problem of the tach gauge bottoming out when I either flip the headlamps over or when I flip the parking lights switch. NOTE: Could this issue be caused by the illuminator switch on the dash? It seems to respond when I decrease the illumination on the dash by allow ing the tach to rise to the 5 mark even though it is at idle at 900rpm. If this is the case. How would I go about bypassing it and still have the interior lights work? or does anyone have one that is in working condition that I could purchase from them.
b) This problem was resolved when I resistance tested the wires and resleeved the ends, as well as, cleaned the sleeve contacts with a wire brush and electrical connector solvent.
c) Same as (b)
d) The AMP light does not light up when I put the ignition in the on position prior to starting the car. NOTE: I had the generator rebuilt twice so far and the person who rebuilt it showed me that if the AMP light does not come on in the car. Then it is not charging the battery. The repairman showed me that the generator was working properly with the regulator attached by hooking it up to a testing machine. The machine showed a positive response to the generator working properly.

I have checked my wiring several times and get no resolution with this issue. Come to think of it. LMAO... I should check the bulb!!! Hahaha... I will post a response later to confirm this most basic oversight. However, I would like to know what everyone thinks about these issues anyway. It will help me with diagnosis if the bulb is in fact good. Which I believe it is since I replaced all of them about 8 months ago.

Thanks in advance for any help given and the help already given to help me bring back this beautiful car.

*I will be posting pictures next time I login and make an update to this thread.*

Thank again.