Advise wanted:Step by step testing new harness
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 893
Likes: 7
From: Hazerswoude-Rijndijk Zuid Holland
Advise wanted:Step by step testing new harness
Hi,
Any one have any advise, tips and tricks to step by step test a newly installed main harness (72' Coupe)?
Any one have any advise, tips and tricks to step by step test a newly installed main harness (72' Coupe)?
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Not really. I install it and connect everything and then turn on those items and make sure they work. before I fully reassemble the dash.
Taking the time to check each and every wire...for me...is a waste of time.
SO if I was connecting all the wires and light sockets to the speedometer and tachometer gauges. I would use one screw to hold the speedo/tach dash panel in place an test it out to make sure the turn signal lights blink..and the gauge lights shine...and the hand brake light and high beam light work. IF they are all good...then I would complete the installation of the speedo/tach dash panel. Then it goes the same for the gauge cluster...test to make sure it all works before I put it all back together by cranking the engine and seeing all of the gauges work and lights work and anything else that needs to work in that area.
DUB
Taking the time to check each and every wire...for me...is a waste of time.
SO if I was connecting all the wires and light sockets to the speedometer and tachometer gauges. I would use one screw to hold the speedo/tach dash panel in place an test it out to make sure the turn signal lights blink..and the gauge lights shine...and the hand brake light and high beam light work. IF they are all good...then I would complete the installation of the speedo/tach dash panel. Then it goes the same for the gauge cluster...test to make sure it all works before I put it all back together by cranking the engine and seeing all of the gauges work and lights work and anything else that needs to work in that area.
DUB
Racer
Joined: Jul 2015
Posts: 396
Likes: 101
From: Lehigh Valley Pennsylvania
I got my car because the PO took the harness out and could not fit it back in. This is what I found when I replaced it.
1. Route it exactly like the AIM shows or it likely will not fit. You will have a nightmare putting your dash panels back in.
2. The PO cut all the plugs off and left the plugs connected to the device. This made it easy to find where the plugs go, but unnecessary. I didn't find any two plugs alike.
3. Don't necessarily assume the harness is at fault if the device doesn't work. My wiper and my AC controller both were bad and the harness (or my wiring) was not at fault when the device didn't work.
4. Make sure all your grounds are good. This is the biggest issue I had when trying to get things to work. There are some good posts on where the grounds are attached.
5. For some reason, missing or defective bulbs caused other bulbs to light or light dimly. Make sure all your bulbs are in and in working order.
6. If you don't have a wiring diagram, get one. If you search this forum you will find an individual that will send you one for free, If you can't find his name, contact me and I will find it for you.
Good luck .
1. Route it exactly like the AIM shows or it likely will not fit. You will have a nightmare putting your dash panels back in.
2. The PO cut all the plugs off and left the plugs connected to the device. This made it easy to find where the plugs go, but unnecessary. I didn't find any two plugs alike.
3. Don't necessarily assume the harness is at fault if the device doesn't work. My wiper and my AC controller both were bad and the harness (or my wiring) was not at fault when the device didn't work.
4. Make sure all your grounds are good. This is the biggest issue I had when trying to get things to work. There are some good posts on where the grounds are attached.
5. For some reason, missing or defective bulbs caused other bulbs to light or light dimly. Make sure all your bulbs are in and in working order.
6. If you don't have a wiring diagram, get one. If you search this forum you will find an individual that will send you one for free, If you can't find his name, contact me and I will find it for you.
Good luck .
Racer
Joined: Feb 2010
Posts: 362
Likes: 10
From: nashville tn
Fuse it
I would remove positive side batter terminal, install a 5 amp fuse between the positive side of the battery and the removed cable for pre testing purposes. If you have a short ckt it will blow the fuse instead of burning up your new harness. You can then increase the fuse size for actual testing of all you componets. Of course you won't be able to crank the engine. Hope it helps, Mike
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
I would remove positive side batter terminal, install a 5 amp fuse between the positive side of the battery and the removed cable for pre testing purposes. If you have a short ckt it will blow the fuse instead of burning up your new harness. You can then increase the fuse size for actual testing of all you componets. Of course you won't be able to crank the engine. Hope it helps, Mike
I have done this so many that if I go to attach the positive battery cable and I hear a POP..I knew I just blew a fuse and stop and nothing gets damaged. And I now know what circuit I have an issue with. Because the fuse being at the positive battery cable is not going to tell me anything but there is a short but not identifying what circuit is causing the 5 amp fuse like you stated you would use at the battery cable popped.
Not saying it did not work for you but I feel it is an odd approach.
DUB
Racer
Joined: Feb 2010
Posts: 362
Likes: 10
From: nashville tn
This is an odd approach to testing the new wiring harness due to it already has fuses in the fuse panel which protects your wires already from a short circuit.. Unless you are referring to the power wires going to the ignition switch and headlight switch ...which are protected by the fusible links at the starter area. or horn relay depending on the year model.
I have done this so many that if I go to attach the positive battery cable and I hear a POP..I knew I just blew a fuse and stop and nothing gets damaged. And I now know what circuit I have an issue with. Because the fuse being at the positive battery cable is not going to tell me anything but there is a short but not identifying what circuit is causing the 5 amp fuse like you stated you would use at the battery cable popped.
Not saying it did not work for you but I feel it is an odd approach.
DUB
I have done this so many that if I go to attach the positive battery cable and I hear a POP..I knew I just blew a fuse and stop and nothing gets damaged. And I now know what circuit I have an issue with. Because the fuse being at the positive battery cable is not going to tell me anything but there is a short but not identifying what circuit is causing the 5 amp fuse like you stated you would use at the battery cable popped.
Not saying it did not work for you but I feel it is an odd approach.
DUB
Racer
Joined: Feb 2010
Posts: 362
Likes: 10
From: nashville tn
an amp meter is great if you have one.
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Thread Starter
Burning Brakes
Joined: May 2006
Posts: 893
Likes: 7
From: Hazerswoude-Rijndijk Zuid Holland
Realy great stuff. I like the bat/fuse approach, for initial install, to finalize i use the normal fuse.
Is there a propper sequence or order to install harnesses.
I'm a long way from cranking the engine
Is there a propper sequence or order to install harnesses.
I'm a long way from cranking the engine
Racer
Joined: Jul 2015
Posts: 396
Likes: 101
From: Lehigh Valley Pennsylvania
I started at the fuse box and connected the engine compartment wiring to it. I went to the driver's dash,center console and passenger side. You can do the rear section and the engine compartment at any time. I really struggled at the center console especially when I went to put it in. Based on what I found when i started wiring, I changed direction and went to a frame off restoration so I can't tell you what you will have to remove to access the wiring. I believe you will have to remove some of the carpets to wire the storage compartments and the rear section. My seat belts had wires to them, so I guess you will have to remove the seats also,
I am not sure what a 5 amp fuse will run. I am certain the wiper motor, blower motor, power windows and head lights draw way more than 5 amps. My guess is the parking lights and the turn signals draw more than 5 amps. I used a spare battery and temporarily connected it at the horn relay junction whenever I wanted to test something. I didn't find any issues with the wiring harness. It laid out well and the plugs were generally where they connected to something. The car was disassembled when I got it so I never drove it. My issues were with devices that failed, not with the harness or the installation.
.
I am not sure what a 5 amp fuse will run. I am certain the wiper motor, blower motor, power windows and head lights draw way more than 5 amps. My guess is the parking lights and the turn signals draw more than 5 amps. I used a spare battery and temporarily connected it at the horn relay junction whenever I wanted to test something. I didn't find any issues with the wiring harness. It laid out well and the plugs were generally where they connected to something. The car was disassembled when I got it so I never drove it. My issues were with devices that failed, not with the harness or the installation.
.