Light problems

This is for "general" electrical discussions. Audio, security, remote start, and power accessories should go here, since they don't seem to fit anywhere else. Not for diesel-specific (like glow systems), or gasoline-specific (like ignition systems) topics.
Adiddas11
Regular Member
Posts: 172
Joined: Fri Nov 20, 2015 7:44 pm
Location: El Mirage, Arizona
Isuzu vehicle(s): 81 chevy luv 4x4 diesel/ 81 chevy luv diesel 2wd/85 chevy s10 diesel(now converting to TD) /1994 isuzu pickup 2.3

Light problems

Postby Adiddas11 » Wed Nov 29, 2017 10:53 am

1) dash light turn on with headlight off, and turn off with headlights on
2) brake lights and turn signal don't work
3) dome light will not turn on
1981 chevy luv diesel

User avatar
Quahlity
Regular Member
Posts: 57
Joined: Sun Aug 13, 2017 4:18 pm
Location: Washington, DC.
Isuzu vehicle(s): 1992 Isuzu pickup 2.3 carb

Re: Light problems

Postby Quahlity » Tue Dec 05, 2017 10:16 am

I have a few questions.
Did all these problems happen at the same time?
Do the dash lights turn on with the running lights off too? I assume you meant with the running lights on, and the headlights off.

The dome light is most likely a bad bulb or door switch.
If the other two cases happened at once check the ground between the engine block and the frame (at the firewall). Seeing as you can test this in your driveway, take (just one side of) a jumper cable and attach it to the engine block, and the other to a good frame point, and see if the it solves the headlight problem.

The rational here is that without a good complete current loop, each additional load (headlights for example) will cause a bigger voltage drop where the loop is bad. It won't affect starting because of the low current relay and direct connection to the battery or running (because it's diesel), but everything else in the truck will be effected.

Adiddas11
Regular Member
Posts: 172
Joined: Fri Nov 20, 2015 7:44 pm
Location: El Mirage, Arizona
Isuzu vehicle(s): 81 chevy luv 4x4 diesel/ 81 chevy luv diesel 2wd/85 chevy s10 diesel(now converting to TD) /1994 isuzu pickup 2.3

Re: Light problems

Postby Adiddas11 » Tue Dec 19, 2017 5:54 pm

update, I fixed the brake light it was a loose connection and the instrument cluster also a loose connection, but I still can not get my turn signals to work, the turn signal lights in the dash do not turn on the flasher relay has no power but has ground and signal could there be another relay I missed mine only had one. where does the relay get power from

Adiddas11
Regular Member
Posts: 172
Joined: Fri Nov 20, 2015 7:44 pm
Location: El Mirage, Arizona
Isuzu vehicle(s): 81 chevy luv 4x4 diesel/ 81 chevy luv diesel 2wd/85 chevy s10 diesel(now converting to TD) /1994 isuzu pickup 2.3

Re: Light problems

Postby Adiddas11 » Mon Dec 25, 2017 1:58 pm

any ideas

User avatar
JoeIsuzu
Site Admin
Posts: 19925
Joined: Thu Aug 19, 2004 9:11 am
Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Re: Light problems

Postby JoeIsuzu » Mon Dec 25, 2017 2:07 pm

In my limited experience, electrical issues can be the hardest to troubleshoot. If they're not one of the common issues like ground connections or a particular connector that commonly goes bad, it's going to come down to you, a wiring schematic, and a multimeter (and some time). The cheapest multimeter from Harbor Freight is adequate for what you'll need. Have you seen the wiring schematics on this site?

Jack

User avatar
puttputtinpup
Regular Member
Posts: 10119
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Light problems

Postby puttputtinpup » Mon Dec 25, 2017 5:45 pm

Jack, did the pups at some point begin using one flasher relay for 4x and turn? I know my 81, 82 pups had 2. If he's missing one, that needs to be fixed. No indicator flashing on the dash may be a loose harness plug at the back of the cluster
Currently P'up-less, but keeping my eyes open for a good deal
Click this link for misc. diesel technical bulletins & other info

User avatar
puttputtinpup
Regular Member
Posts: 10119
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Light problems

Postby puttputtinpup » Mon Dec 25, 2017 6:23 pm

try cycling the 4way flasher switch on the clamshell a few times..after installing the missing flasher relay (81 should have 2. One for turn, the other for 4ways.)
Currently P'up-less, but keeping my eyes open for a good deal
Click this link for misc. diesel technical bulletins & other info

Adiddas11
Regular Member
Posts: 172
Joined: Fri Nov 20, 2015 7:44 pm
Location: El Mirage, Arizona
Isuzu vehicle(s): 81 chevy luv 4x4 diesel/ 81 chevy luv diesel 2wd/85 chevy s10 diesel(now converting to TD) /1994 isuzu pickup 2.3

Re: Light problems

Postby Adiddas11 » Tue Dec 26, 2017 9:29 am

I bought a wiring harness that is not from a 81 its a newer one i didn't realize it untill i installed it. I think its from a 84-87 wiring harness because its way different then the diagram on the forum

Adiddas11
Regular Member
Posts: 172
Joined: Fri Nov 20, 2015 7:44 pm
Location: El Mirage, Arizona
Isuzu vehicle(s): 81 chevy luv 4x4 diesel/ 81 chevy luv diesel 2wd/85 chevy s10 diesel(now converting to TD) /1994 isuzu pickup 2.3

Re: Light problems

Postby Adiddas11 » Fri Dec 29, 2017 8:59 am

Are there different combination switches

User avatar
puttputtinpup
Regular Member
Posts: 10119
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Light problems

Postby puttputtinpup » Fri Dec 29, 2017 2:28 pm

Well I know this, the turn signal and 4way circuits are different. The power to the cig lighter on newer trucks turns on with key. Older ones like 81, 82 the cig lighter is powered all the time.

Several years ago, I had pulled a combination switch from a trooper that had delay wiper feature. I thought it'd be plug&play upgrade to my 82 pup. It didn't work. So I reinstalled the old switch. The plugs were wired differently. Might have worked had I know which wires to swap around. Not sure what year the wiring changed...guessing 84. My 84 automatic and 85 LS had a locking steering wheel and door open buzzer with key in ignition.

So, simply if you could get the combo switch and ignition switch (or entire steering column) that went with the harness, you might be in business. Otherwise, wires will need to be swapped around in the plug to get things working.
Currently P'up-less, but keeping my eyes open for a good deal
Click this link for misc. diesel technical bulletins & other info

User avatar
JoeIsuzu
Site Admin
Posts: 19925
Joined: Thu Aug 19, 2004 9:11 am
Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Re: Light problems

Postby JoeIsuzu » Sun Dec 31, 2017 10:19 am

Adiddas11 wrote:Are there different combination switches

As far as I know, the later ('83-'87) combination switches are backward compatible, EXCEPT that the intermittent wiper feature will not work on the '81-'82 harnesses.

The 1984-1991 Trooper switches are also interchangeable. And last time I checked, rockauto.com listed these in their catalog.

Jack

Adiddas11
Regular Member
Posts: 172
Joined: Fri Nov 20, 2015 7:44 pm
Location: El Mirage, Arizona
Isuzu vehicle(s): 81 chevy luv 4x4 diesel/ 81 chevy luv diesel 2wd/85 chevy s10 diesel(now converting to TD) /1994 isuzu pickup 2.3

Re: Light problems

Postby Adiddas11 » Sun Dec 31, 2017 6:27 pm

Update i go the turn signal to work the wiring harness is from a 87 so the turn signal had to be change i noticed that the connections where different and went to check out a pup at the junk yard and found the right one but it was broken so i bought a new one and now it works thanks for your help

User avatar
puttputtinpup
Regular Member
Posts: 10119
Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Light problems

Postby puttputtinpup » Sun Dec 31, 2017 8:38 pm

Great news. Glad it's working now and happy to help
Currently P'up-less, but keeping my eyes open for a good deal
Click this link for misc. diesel technical bulletins & other info


Return to “Electrical Troubleshooting, Maintenance, and Upgrades”

Who is online

Users browsing this forum: No registered users and 1 guest