Why This Loom Fails — and Why It's Always the Same Place
The K5 Blazer two-door tailgate carries several electrical circuits — reverse lights, number plate lights, rear washer pump and rear wiper motor if fitted. The wiring that serves these circuits has to travel from the body of the truck, through the tailgate hinge, and down into the tailgate itself.
That hinge flexes every single time the tailgate is opened or closed. Over 30 years in a climate where the insulation on the wire becomes brittle and the copper work-hardens, the wires inside the loom crack and fail — almost always at the hinge flex point where the stress is concentrated. The failure is typically internal, meaning the outside of the loom looks intact. The wire has broken inside its insulation, which is why the fault appears intermittent — the broken ends touch and separate as the tailgate moves.
This is one of the most misdiagnosed faults on the K5. Mechanics replace bulbs, check fuses, test relays — and the problem comes back because the break in the loom is invisible. Once you know what you're looking for, the diagnosis is straightforward and the repair is permanent.
Quick diagnosis test: With the tailgate closed and the ignition on, engage reverse and observe the reverse lights. Now slowly open the tailgate while watching — if the lights flicker, change brightness or come on as you move the tailgate, the hinge loom has failed. The fault is mechanical, not electrical.
Circuits Carried by the Tailgate Hinge Loom
Wire colours are typical for the K5 production run. Verify against your specific truck before cutting anything — colours can vary between model years and previous repair history.
What You Actually Gain
What You Need
For a Proper Repair — Build New Rather Than Patch Old
- Automotive wire — various gauges, matching original colours where possibleSharjah electrical suppliers — 1.5mm² minimum for all circuits
- Flexible conduit / loom tape — heat and abrasion resistantAuto electrical suppliers — the flex-resistant type specifically
- Weatherproof connectors — for body to loom junction pointsDeutsch DT series or equivalent sealed connectors
- Heat shrink — adhesive lined, various sizesAny electrical supplier
- Dielectric greaseAll connector and bulb holder connections
- Reverse light bulbs (replace while in there)Check existing type — typically 1156 or 921
- Number plate light bulbsInspect and replace if aged
Do not splice and tape the existing loom. Splicing the broken wire inside the existing loom and wrapping with tape is a temporary fix that will fail again — often sooner than the original, because the splice adds a stiff point that concentrates flex stress differently. The correct repair is a new loom section routed through the hinge with appropriate flex-resistant conduit.
What It Will Cost (AED)
| Item | Source | Est. Price (AED) |
|---|---|---|
| Automotive wire (per metre, various colours) | Sharjah electrical suppliers | 5 – 10 per metre |
| Flex conduit / loom tape | Sharjah electrical / auto suppliers | 30 – 60 |
| Weatherproof connectors (set) | Sharjah electrical suppliers | 40 – 80 |
| Heat shrink, dielectric grease | Any auto / electrical parts | 20 – 40 |
| Bulbs (reverse + number plate) | Any auto parts | 20 – 40 |
| Labour — auto electrician | Sharjah Industrial auto electrician | 150 – 300 |
| Total | 260 – 530 |
This job benefits from an experienced auto electrician in Sharjah who knows OBS trucks. The diagnosis is the hard part — once identified, the repair itself is straightforward.
Where to Find the Parts
Sharjah — Electrical Suppliers
- Sharjah Industrial Area — automotive wire by the metre
- Ask for flex-resistant loom conduit specifically
- Deutsch DT connectors — specialist electrical shops
- Al Quoz Industrial — Dubai alternative
Auto Electricians — Sharjah
- Sharjah Industrial Area auto electricians
- Show this guide and the wire map above
- A good auto electrician will have seen this fault before
Unlike many jobs in this guide, this one genuinely benefits from a skilled auto electrician rather than a general mechanic. The diagnosis and routing require experience with looms.
The Process
- Disconnect the battery negative terminal before any work on electrical circuits.
- Open the tailgate fully. Locate the hinge loom — it runs from the body pillar through the hinge knuckle into the tailgate. The failure point is almost always within 100mm either side of the hinge pivot.
- With the tailgate in various positions, probe each wire with a multimeter — the broken wire will show continuity when the tailgate is in one position and open circuit in another. This confirms the fault location before cutting anything.
- Remove the existing loom from the hinge area. Unclip the conduit and note the routing carefully — photograph before removing.
- Cut new wire lengths with 150mm extra at each end for connections. Route through the hinge using flex-resistant conduit — the conduit must be able to flex without kinking at the hinge pivot point.
- Connect new wires at the body end using weatherproof connectors — never bare twisted joins in a location exposed to moisture and flex.
- Connect at the tailgate end to the original circuit. Protect all connections with adhesive heat shrink and dielectric grease.
- Secure the new loom to the hinge with cable ties — leave enough slack at the pivot point to allow full tailgate movement without tension on the wires.
- Reconnect battery. Test all circuits through full tailgate movement — open, closed, halfway. All lights should function in every position.
- Replace bulbs in reverse lights and number plate lights while access is easy.
Hand This Over
"The rear electrical fault on this K5 Blazer is caused by broken wires inside the tailgate hinge loom — the wires crack at the flex point where the loom passes through the hinge. Do not splice the existing wires — build a new loom section using flex-resistant conduit through the hinge. Use weatherproof connectors at both ends, not bare twisted joins. Leave enough slack at the hinge pivot for full tailgate movement. After repair, test all circuits with the tailgate moving through its full range of motion — the fault only shows when the tailgate is in the right position."
This Guide Applies To
This guide is specific to the two-door K5 Blazer without a rear window winding mechanism. The failure mode is the same across all K5 model years but the wire routing may vary slightly between 1992–1994 production.
What You've Now Got
✓ An OBS That Actually Works Electrically
Grounds sorted, headlights running at full power, and the rear loom repaired properly. The electrical gremlins that drove everyone — including the mechanics — quietly insane are gone. The truck now has a solid electrical foundation for anything else you want to add. And you can see where you're going at night, which was arguably overdue.