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90 voltage gauge problem

pomerom

NAXJA Forum User
Location
North Florida
I have a 90 Cherokee Laredo. One owner -- stock -- 43,000 miles.

Almost new battery and the alternator was replaced with NAPA's best aprox. 6 months ago.

Everything seems to be working fine except the in-dash voltmeter.

Readings taken across the battery terminals (with multiple meters just to make sure) show it working within normal specks.

However the in-dash voltmeter seems to respond very slugishly, if at all as lights are turned on, car is started, etc. If it does show movement it seems to always be in the direction one would expect.

I cannot locate the 'sending unit' -- where the factory voltmeter gets its input. And at the moment I cannot remove the instrument assembly because there has been an 'anti-theft' collar installed that is in the way. (If anybody knows how to remove this collar without damaging the steering column I'd love to know that too -- have one on this vehicle and my 82 CJ8. Want them both off!!)

So what now?

Can somebody please give me some advice on where to go next? What to do??

Your advice and suggestions will be most appreciated.

Thanks .....

Mike
 
The RENIX voltmeter is a notorious liar (I have five - none of them are right!) and I'm inclined to think they have some sort of buffer - rather like a DMM.

I just haven't bothered to figure out why - I put a red grease pencil mark on the window right where "normal" has settled down to be, and check it if it wanders off the mark consistently. Given time, I can probably check to see where the IP voltmeter gets its input - I just haven't bothered yet. However, I'd back-check your battery reading both at the alternator output post and at the screwpost on the start relay - make sure they agree.

Also, check the ground strap from the engine to the firewall (driver's side rear of the cylinder head,) I never did like that thing, and it causes no end of trouble.

As for the "anti-theft" collar - if it's like the one they have in JCWitless, you can probably cut it off with a Dremel and a hanful of fibre-reinforced cut-off wheels - but it would take time. I haven't seen one in person, so I'm not sure of any other ways to deal with it - but I'm fairly sure it's a pain to remove with conventional field tools, or it would defeat the purpose. Got pix? All angles would be helpful...
 
On my 90, I too have noticed the OEM volts gauge to be a ball park figure. I simply cut the copper on the printed circuit on the back of the gauge cluster going to the volt gauge. I then took a 16awg speaker wire with 2x ring terminals and connected directly to the gauge and battery with a relay for the shunt. The volt gauge can only be as accurate as the information it is recieving, which in this case is downstream of lighting/ignition circuits.
 
Thanks for the info.

Unless something changes I think I'll take the advice to just look for major changes in the reading -- and monitor the performace mostly by watching the battery itself.

At least for a while ...

Mike
 
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