electrical problem in 86 CJ - Jeeps Canada

Grogsjeep · 02-07-2010, 02:55 PM

My son and I recently picked up an 86 CJ as a project rebuild. We put in a new battery and drove it about 20km home. When we tried to restart it a couple od days later the battery was completely dead. We have since changed the alternator and recharged the battery, but it seems to drain on its own without anything being on. When we disconnect the positive the voltage actually climbs but only gets to about 7v.
Neither of us have any mechanical experience, but we would like to be able to do the work ourselves, any suggestions where we can look?

Savasa · 02-07-2010, 10:23 PM

Greetings,
Congrat's guys! I know little to nothing SPECFICALY about CJ's but can offer some "generic" information. First, if you haven't got one yet, go to Can' Tire (for example) and buy a Chilton manual that covers YOUR year and model of Jeep. This should give you some idea of wiring and more. Next buy an inexpensive VOM or two (for when you fry the first one-usually can get them for about $10 ea.).
OK, got manual, VOM, tools, fire extinguisher and SAFETY GLASSES? Disconnect BOTH battery cables and put on charge (it may give you more space to take the battery right out). Check your + and - connections to both the block (-) and to the starter (+). Remove connections, clean well and put back on.
Sounds like you'ved got a short circuit somewhere. That about exhausts my advice thus far.
Peter.

bigdan · 02-08-2010, 08:58 AM

do you have the original analog clock in the dash .....
I had that problem in my CJ .... it pulls some voltage... if jeep not used every day , it drains the battery

jeepthing · 02-08-2010, 04:17 PM

i had the same problem with my 84 cj7, it turned out to be the headlight switch in the dash,it was shorting out allowing power to go to the headlights but not enough to light them up

Grogsjeep · 02-10-2010, 11:00 PM

Thanks everyone for the advice. We charged the battery and started checking for shorts. We attached a test light and by moving the probe around watched whether it went dimmer or brighter. Luckily for us we heard a click after a few minutes of charging and discovered a relay switch near the firewall that was the problem. Not sure what the relay was for, but I was able to remove it (its a small square box), clean the contacts and stick it back and the problem went away. The battery is still holding a proper charge.

Savasa · 02-11-2010, 08:25 AM

Good for you guys. I would suggest checking ALL your wiring/connections if you've a mind to. Clean 'em up and put on some no corrode grease. Sort of preventive maintenance as it were. If you've no idea of previous service of the vehicle, this would also be a good time to change fluids (diff', transfer case etc.). One of the first things I do when I get a used vehicle home is to de-grease the engine and drive train. This allows me to spot any leaks (either existing or new) and address them.
Have fun.
Peter.