Hesitation when lights are on

[Danny_m]

Hi I’m new here and I’ve got a question for anyone that can help me out I’ve got a 1985 ranger with the 2.9L engine in it and when I’m driving and I turn the lights on the vehicle starts to hesitate a lot note it does had LED lights. I’m a bit new to working on cars especially older stuff like this. Because the engine was swapped from a 86 ranger the wiring under the hood is a bit messy but I’d like to know if anyone can point me into a direction to start looking, Thank you I appreciate any help

 

[Uncle Gump]

Just drive during daylight hours... easy peasy.




Seriously... lighting systems and ignition/fuel systems are totally unrelated electrically.

A common point could be battery voltage. Have you had a voltmeter on the battery to see what happens when you turn the lights on?

 

[Curious Hound]

Sounds like bad connections or the alternator is going bad. Need to know battery voltage at rest, engine off, after several hours. Then, battery voltage with engine running, at least 5 minutes after starting. When inspecting connections, both positive connections AND negative (ground) connections are important. Check for tightness and cleanliness. No rust. No corroded wires. No paint between lugs and frame or body.

(Conjuring up my best @Ron D impersonation until he gets home)

 

[RobbieD]

Welcome to TRS.

Nothing wrong with not having a lot of experience working on cars; it's where every one of us started.

A couple of basic things to do first, with a beginner in mind.

1) Check that both battery post terminals are tight, and have no corrosion. It'd be good to take each off and clean the contact areas, and it would be even better to spend a couple of bucks and get a battery post and terminal cleaning brush. Be careful around the battery; disconnect and remove the negative side, then do the positive side completely (remove, clean, reinstall) before you return to negative, cleaning and reinstalling it. Doing things in that order reduces the chances of your tools shorting the battery while you're working on it.

2) Check that your truck has all of these grounding wires: a) thick cable from the battery negative, going through a clamp on the frame and then to the engine; b) a smaller thick wire from the battery negative to the fender apron; c) another thick wire, or braided wire, from the back of the engine to the firewall. Pay attention that none of these are connections are loose, and that there is no green powdery corrosion anywhere on the cables or terminals.

3) Carefully look over the "messy" wiring and make sure that no wires have bare spots or are loose. Just use common sense.

Beyond those basics you're looking at testing the battery's voltage, and alternator output. Best to start with little steps and move up to bigger steps as you go.

Good luck!

 

[RobbieD]

(Conjuring up my best @Ron D impersonation until he gets home)

Damn; I thought that RonD was back.

Good job, Eric!