Voltage problem

I have an 89 Cherokee 4.0 that I just bought. The alternator was recently replaced and the battery is newer. It runs fine but every accessory works slow, lights are dim, wipers barely move, and the voltage gauge just reads just over 9. It starts fines every time so there is no drain on the battery. I drove it 2 hours home with no problems. I put a meter on the battery while its running and its shows 14.6. Any ideas what else I can check or what could be wrong with it.

racinXJ said:

I have an 89 Cherokee 4.0 that I just bought. The alternator was recently replaced and the battery is newer. It runs fine but every accessory works slow, lights are dim, wipers barely move, and the voltage gauge just reads just over 9. It starts fines every time so there is no drain on the battery. I drove it 2 hours home with no problems. I put a meter on the battery while its running and its shows 14.6. Any ideas what else I can check or what could be wrong with it.

Click to expand...

14.6VDC at the battery terminals is a bit high when it's running - but borders on acceptable. I'm assuming that was at idle, right?

What other electrical loads did you have on at the time?

Have you checked grounds? Partcularly the "RENIX Killer" ground - between the cylinder head stud and the firewall. Since the lighting, the wipers, the gages, et al all ground via the chassis, and the primary chassis ground is that silly little strap, it's reasonble to check that as your potential failure first.

Check, clean, and replace PRN. While you're about it, you may want to add a secondary ground directly between the battery and the chassis - use at least 10AWG wiring, and clean the contact patch between the chassis and the ring lug down to bare metal and apply corrosion inhibitor on assembly.

NB: "Corrosion inhibitor" does not mean "liquid electrical tape," nor does it mean "WD-40." In this case, both of those are likely to cause more problems than they'd cure! You can find electrical corrosion inhibitor in the electrical section of any well-stocked hardware/DIY store. A one-ounce tube of the stuff should last you a couple of years or so (and that's assuming you go through and clean/service all if your chassis grounds with the stuff!)

But, it is certainly possible for you to have strong output from the alternator and it doesn't make it to the accessories on RENIX - simply because the grounds aren't any good (kinda like how engines work - if you clean up your intake, you must clean up your exhaust to do any good. If you can't get air out, you won't be able to get any more air in.)

Do as 5-90 suggests.

You should consider getting some upgraded cables. Here is one very good article: http://www.olypen.com/craigh/charge.htm

You can buy upgraded cable sets. I bought mine from a member (thanks for the excellent cable set, 5-90).

I had already replaced both positive and negative cables, and checked the one ground that goes from the block to the body. I did overlook the second from the valve cover to the body. It was broken, but both ends were behind the misc. harness' and vac lines. Anyhow, point being, it was broken! Fixed that and BOOM!! EVERYTHING WORKS AS IT SHOULD. All gauges came back, wipers working, lights are bright! Thanks for All your help!! Im ready for the Woods!!