RA28 dash electric problems. Help please?? :)

[Gunna]

Hey guys,

So my dash has had this problem for a while now and I'm thinking i need to take a look at it. I haven't due to not knowing where to start really... Here is what its doing...

All gauges are effected other than the speedo.

When i start the car the gauges don't work at all, then when i rev the car above about 2,000-3,000 rpm they turn on but kind of only half work, they stay half turned on from that point on. The charge light become half bright but the oil light doesn't light up at all. The tacho works but doesn't fully work the engine revs more than displayed... The fuel and temp gauges both just sit just about empty and cold not matter the temp or fuel level (until empty)..

I have checked fuses and all seems ok to me.

Has anyone else had this problem? Is it an easy fix or do i need to take it to an auto electrician?

Any help is much appreciated

[ra_28]

Check the round plugs on the back of the gauges I had problems with them giving me strange reading on the temp and fuel and no charge light. Found they had a bad connection on the power wire. Cleaned all the terminals and adjusted the female pins for better contact and my problem was solved.

Alex

[ToyTA22]

Try as RA_28 suggested i.e check connections. After checking connection to power supply get alternator output checked, usually dim charge light indicates damaged diodes in alternator.

There are a number of other people who may have suggestions on here as well.

[ta22fan]

Sounds like you've got low voltage to your instruments. The reason your speedo is working fine is because it is mechanical not electrical (driven by cable direct from your gearbox). Check the general health of your electricals (battery & alternator) to start with. If these check out, it'll most likely be a bad joint or connector somewhere in the wiring loom to the instrument cluster - which could take some finding....

[Gunna]

Thanks heaps guys! Will check out Alternator as its a pretty old one and it could be the source of my problems. I hope so anyway

[o_man_ra23]

If it's affecting everything like that, I would be wagering its a bad earth. Wire colour is white/black. Check for corroded joins, loose terminals etc.

[Gunna]

Its also effecting the headlights, they will turn on but once i begin to drive it and it reaches higher rpms they get a bit brighter...

Are you talking about the earth at the battery or a different location?

[Javal]

If it's affecting everything like that, I would be wagering its a bad earth. Wire colour is white/black. Check for corroded joins, loose terminals etc.

This is what i'd be checking also.

Its also effecting the headlights, they will turn on but once i begin to drive it and it reaches higher rpms they get a bit brighter...

Are you talking about the earth at the battery or a different location?

Checking the earth in on the battery and on the body next to the battery tray are a great start. For your instrument problems I would be checking the earth for the dash electrics, usually these are in the kick panels. Instrument earth is usually in the RH kick panel. White wire, black trace (black stripe on wire) with an eye terminal bolted to the body. There may be one in the LH kick panel too which would be worth checking - usually that's for the HVAC (blower fan and such).

As for your headlights being dim and then picking up with revs, that sounds like your alternator is failing to keep up with demand, which is not uncommon on older cars. You should get out a multimeter, check the battery voltage with the engine idling, the reading should be around 13.7v give or take a bit. Then with the engine idling, turn on the high beams and blower fan and check it again - you wouldn't want it to go below 12.5 - 12.7v. It's worth checking at any rate.

My car does this too, with an 85a alternator, fully rewired H4 and H1 headlights with near zero voltage drop. The fact of the matter is that it can't crank out enough amperage at low RPM.

Anyway here's what i'd be doing -

Checking your battery terminals are clean and tight, because it's easy
Checking your earth strap from the battery to the body is clean and tight
Popping off the RH kick panel and checking the earth there
Check the plugs on the instrument panel are seated correctly and no corrosion is present
Checking alternator output, although I believe this is unrelated.

Further testing may be required.

[Gunna]

Thanks heaps! That is exactly what i need as I'm not super mechanical but enough to be able to follow those steps! Thanks so much!!

[o_man_ra23]

There may also be an instrument earth under the dash, behind the instruments. Can't quite remember on this.