4X4 light
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Mountain Pass
Joined: Dec 2003
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4X4 light
I am changing a 2wd to a 4wd and was wondering if anyone knows where the wire would be to hook up the 4X4 light in the dash? It is an 88 F150 Lariat. Is this pre-wired in the harness or do I need to add it somehow?
Posting Guru
Joined: Jan 2002
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From: Baltimore
Here's the schematic that shows the dash indicators for 4 HI and 4 LO.
Disregard the left part of the schematic since it's for the electronic shift transfer case.
Screwed into the transfer case is a mechanical switch. When you shift into 4 HI, the Light Blue wire is grounded and the 4 HI indicator lights in the dash cluster. When you shift into 4 LO the Light Blue/Black wire is grounded which turns on the 4 LO indicator in the dash cluster.
I don't believe there is a factory wiring harness for this switch if you have a 2wd truck.
If you look under the hood at the round harness that comes out of the firewall on the driver side below the brake master cylinder the Light Blue and Light Blue/Black wire are in that bundle of wires. You can splice into the two wires and run some new wire to the transfer case switch.
Disregard the left part of the schematic since it's for the electronic shift transfer case.
Screwed into the transfer case is a mechanical switch. When you shift into 4 HI, the Light Blue wire is grounded and the 4 HI indicator lights in the dash cluster. When you shift into 4 LO the Light Blue/Black wire is grounded which turns on the 4 LO indicator in the dash cluster.
I don't believe there is a factory wiring harness for this switch if you have a 2wd truck.
If you look under the hood at the round harness that comes out of the firewall on the driver side below the brake master cylinder the Light Blue and Light Blue/Black wire are in that bundle of wires. You can splice into the two wires and run some new wire to the transfer case switch.
Posting Guru
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From: Baltimore
The dash cluster has 2 indicators for 4x4.
The first one indicates 4x4 same as 4 Hi.
The other indicator is LO range
Here's a pic. of the dash cluster. The two yellow arrows point to the bulbs.
I've also included a pic of the back of the cluster which shows the bulb holders. It's possible there are no bulbs in the sockets for 4x4 or LO range.
If you pull the front dash bezel off you should see light bulbs in the two sockets.
The first one indicates 4x4 same as 4 Hi.
The other indicator is LO range
Here's a pic. of the dash cluster. The two yellow arrows point to the bulbs.
I've also included a pic of the back of the cluster which shows the bulb holders. It's possible there are no bulbs in the sockets for 4x4 or LO range.
If you pull the front dash bezel off you should see light bulbs in the two sockets.
Posting Guru
Joined: Jan 2002
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From: Baltimore
This is a picture of the connector at the fire wall under the hood driver side.
To seperate the connector at the firewall end you need to back off the center bolt that keeps the connector together. This will allow you to pull the connector off and give you a better view of the wires.
This picture shows the two wires. Light Blue and Light Blue/Black.
To seperate the connector at the firewall end you need to back off the center bolt that keeps the connector together. This will allow you to pull the connector off and give you a better view of the wires.
This picture shows the two wires. Light Blue and Light Blue/Black.
Thread Starter
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Mountain Pass
Joined: Dec 2003
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OK maybe I should also mention that I have installed a NP205 transfer case which has only one sending unit in it. Should I assume that only one light will work? Does the T-18 have two sending units for two wires? I think the T-18 would have been OEM in that year.
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Posting Guru
Joined: Jan 2002
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From: Baltimore
Might want to post a question about the NP205 indicator switch in the Forums for the older trucks that used it.
There is a forum for Clutch, Transmission, Differential and Transfer Cases.
At the top of the page top left side, click on Forums then scroll down to view the different Forums.
I believe the Borg Warner 1345 and 1356 was used from 87-96 on the F series trucks. The indicator switch is a single unit with a two wire connector end.
There is a forum for Clutch, Transmission, Differential and Transfer Cases.
At the top of the page top left side, click on Forums then scroll down to view the different Forums.
I believe the Borg Warner 1345 and 1356 was used from 87-96 on the F series trucks. The indicator switch is a single unit with a two wire connector end.
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Thread Starter
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Mountain Pass
Joined: Dec 2003
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Yes you are right, I cannot find what wire will light that indicator. I grounded that blue one and the blue black and the anti lock light came on. Go figure. I assume though if there is a wire for it there must be a plug end somewhere. Where would it be hiding? There is one on the firewall but it energizes the fuel pump. Why is that or what would be the purpose?
Posting Guru
Joined: Jan 2002
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From: Baltimore
The two wires are in the bundle of wires in the round connector plug at the firewall under the hood drive side.
You must have the wrong wires. Should be Light Blue and the other wire is Light Blue with a Black stripe. Sometimes it's hard to tell the color of the wire because of the dirt and heat from the engine bay can cause the color of the wire to lighten up. Example a Yellow wire can look White.
If you look closely at the connector there are small numbers imprinted in the connector. I'll look up the number of the two wires and re-post.
You must have the wrong wires. Should be Light Blue and the other wire is Light Blue with a Black stripe. Sometimes it's hard to tell the color of the wire because of the dirt and heat from the engine bay can cause the color of the wire to lighten up. Example a Yellow wire can look White.
If you look closely at the connector there are small numbers imprinted in the connector. I'll look up the number of the two wires and re-post.
Posting Guru
Joined: Jan 2002
Posts: 1,346
Likes: 8
From: Baltimore
If you look at the connector think of it as a circle with 3 rows..
The outer ring as row #1, middle ring row #2 and inner ring row #3.
The two wires you need are in the middle ring (#2 in the pic.)
The Light Blue wire in the 2nd ring has a Brown wire next to it on one side and a Light Blue/Red wire on the other side of it.
The Light Blue/Black wire in the 2nd ring has a Black/Pink wire next to it on one side and a Yellow/Light Green wire on the other side.
With the igniton on, grounding the Light Blue wire should turn on the 4x4 light in the dash.
Grounding the Light Blue/Black wire should turn on the 4 Lo light.
